Jihad in arabic means 'struggle to strive for a particular cause' which is a relatively generic term and could therefore apply to many aspects of the life of an adherent. There are two different types of Jihad which the Qur'an differentiates between. Lesser Jihad refers to the act of struggle against oppression and injustice towards God's people. Greater Jihad refers to inner spriritual striving to avoid sin in Islam.
Haddith quotes about Jihad 
1. Sahih Bukhari 4:52:50 "The Prophet said, 'A single endeavor of fighting in Allah's Cause is better than the world and whatever is in it.'"
2. Sahih Muslim 20:4706 Messenger of Allah said: Whom do you consider to be a martyr among you? They (the Companions) said: Messenger, of Allah, one who is slain in the way of Allah is a martyr. He said: Then (if this is the definition of a martyr) the martyrs of my Umma will be small in number. They asked: Messenger of Allah, who are they? He said: One who is slain in the way of Allah is a martyr; one who dies in the way of Allah, is a martyr; one who dies of plague is a martyr; one who dies of cholera is a martyr.
3. Sahih Bukhari 4:52:63 "A man came to the Prophet and said, 'Shall I Fight or embrace Islam first?' The Prophet said, 'Embrace Islam and then fight.' He became a Muslim and was died syahid. The Prophet said, 'A little work, but a great reward."
4. Sahih Bukhari 4:52:63 "A man whose face was covered with an iron mask came to the Prophet and said, 'Allah's Apostle! Shall I fight or embrace Islam first?' The Prophet said, 'Embrace Islam first and then fight.' So he embraced Islam, and was syahid(died in Allah’s cause). Allah's Apostle said, 'A Little work, but a great reward.'"
5. Sahih Bukhari 4:53:386 "Our Prophet ordered us to Fight you till you worship Allah alone or pay us the Jizyah tribute tax in submission. Our Prophet has informed us that our Lord says: 'Whoever amongst us is killed as a syahid shall go to Paradise to lead such a luxurious life as he has never seen, and whoever survives shall become your master.'"
6. Sahih Muslim 20:4668 "The Messenger said: 'Anybody who equips a warrior going to Fight in the Way of Allah is like one who actually fights ."
7. Sahih Muslim 1:29 "Command For fighting: When the Messenger breathed his last and Bakr was appointed Caliph, many Arabs chose to become apostates [rejected Islam]....Abu Bakr said: 'I will definitely Fight against anyone who stops paying the Zakat tax, for it is an obligation. I will Fight against them even to secure that which they used to pay if they withhold it now.' Allah had justified fighting against those who refused to pay Zakat."
8. Muslim:C9B1N33"The Prophet said: 'I have been commanded to Fight against people till they testify there is no god but Allah, that Muhammad is the Messenger of Allah, and they establish prostration prayer, and pay Zakat. If they do it, their blood and property are protected.'"
9. Narrated By Ibn 'Abbas : " The Prophet said, on the day of the Conquest of Mecca, "There is no migration (after the Conquest), but Jihad and good intentions, and when you are called for Jihad, you should immediately respond to the call.'"
10. Muslim:C28B20N4628 "Allah has undertaken to provide for one who leaves his home to fight; Allah will either admit him to Paradise or will bring him back home with his reward and booty."
11. Muslim:C28B20N4629 "The Messenger said: 'One who is wounded in the Way of Allah will appear on the Day of Judgment with his wound still bleeding. The color (of discharge) will be blood, (but) its smell will be musk.'"
12. Sahih Bukhari 4:53:386 "Our Prophet has informed us that our Lord says: 'Whoever amongst us is killed as a syahid shall go to Paradise to lead such a luxurious life as he has never seen, and whoever survives shall become your master."
13. Muslim: C34B20N4652-3 "The Merit Of Jihad And Of Keeping Vigilance Over The Enemy: A man came to the Holy Prophet and said: 'Who is the best of men?' He replied: 'A man who fights staking his life and spending his wealth in Allah's Cause.'"
14. Muslim:C42B20N4684 "A desert Arab came to the Prophet and said: 'Messenger, one man fights for the spoils of war; another fights that he may be remembered, and one fights that he may see his (high) position (achieved as a result of his valor in fighting). Which of these is fighting in the Cause of Allah?' The Messenger of Allah said: 'Who fights so that the word of Allah is exalted is fighting in the Way of Allah.'"
15. Muslim:C53B20N4717 "The Prophet said: 'This religion will continue to exist, and a group of people from the Muslims will continue to Fight for its protection until the Hour is established.'"
16. Sahih Bukhari 4:52:44 "A man came to Allah's Apostle and said, 'Instruct me as to such a deed as equals Jihad in reward.' He replied, 'I do not find such a deed.'"
17. Sahih Bukhari 1:2:25 "Allah's Apostle was asked, 'What is the best deed?' He replied, 'To believe in Allah and His Apostle Muhammad.' The questioner then asked, 'What is the next best in goodness?' He replied, 'To participate in Jihad, religious struggle in Allah's Cause.'"
18. Sahih Bukhari 4:53:412 " Narrated By Ibn 'Abbas : The Prophet said, on the day of the Conquest of Mecca, "There is no migration (after the Conquest), but Jihad and good intentions, and when you are called for Jihad, you should immediately respond to the call."
19. Sahih Bukhari 4:52:65 "A man came to the Prophet and asked, 'A man fights for war booty; another fights for fame and a third fights for showing off; which of them fights in Allah's Cause?' The Prophet said, 'He who fights that Allah's Word, Islam, should be superior, fights in Allah's Cause.'"
20. Sahih Muslim 20:4676 <Chapter 40 of Book 20 in Sahih Muslim: JIHAD NOT COMPULSORY FOR THOSE WHO HAVE A GENUINE EXCUSE>
21. Sahih Muslim 20:4676 Believers who sit home and those who go out for Jihad in Allah's Cause are not equal.
22. Sahih Bukhari 4:52:216 "Allah's Apostle said, 'Were it not for fear it would be difficult for my followers, I would not have remained behind any army units. No doubt I wish I could Fight in Allah's Cause and be syahid(die in the way of Allah) and come to life to be syahid again.'"
23. Sahih Bukhari 4:52:45 "Someone asked, 'Allah's Apostle, who is the best among the people?' He replied, 'A believer who strives his utmost in Allah's Cause with his life and property.'"
24. Sahih Bukhari 4:52:48 "The people said, 'Allah's Apostle! Acquaint the people with the good news.' He said, 'Paradise has one hundred grades which Allah has reserved for the Mujahidin who Fight in His Cause.'"
25. Sahih Bukhari 4:52:66 "Allah's Apostle said, 'Anyone whose feet get covered with dust in Allah's Cause will not be touched by the Hell fire.'"
26. Sahih Bukhari 4:51:72 "Our Prophet told us about the message of our Lord: 'Whoever amongst us is killed will go to Paradise.' Umar asked the Prophet, 'Is it true that our men who are killed will go to Paradise and the Pagan's will go to the Hell fire?' The Prophet said, 'Yes.'"
27. Sahih Bukhari 4:52:94 "The Prophet said, 'Whoever spends two things in Allah's Cause [his life and his wealth], will be called by all the gatekeepers of Paradise.'"
28. Sahih Bukhari 4:52:43 "Aisha(the Apostle Muhammad’s wife) said, 'Apostle! We consider Jihad as the best deed. Should we not Fight in Allah's Cause?' He said, 'The best Jihad for women is the Hajj done as I have done it.'"
29. Muslim:C34B20N4669"The Prophet said: 'He who equips a warrior in the Way of Allah is like one who actually fights and he who looks after the family of a warrior in the Allah's Cause in fact participated in the battle.'"
30. Muslim:C29B20N4636"The Messenger of Allah was asked: 'What deed could be equivalent to Jihad in the Cause of Allah? He answered: 'You do not have the strength to do that deed.'The question was repeated twice or thrice. Every time he answered: 'You do not have the strength to do it.' When the question was asked for the third time, he said: 'One who goes out for Jihad is like a person who keeps fasts and stands in prayer forever, never exhibiting any weariness until the Mujihid returns from Jihad.'"
31. Muslim:C30B20N4639"The Messenger said: 'Leaving for Jihad in the Way of Allah in the morning or in the evening will merit a reward better than the world and all that is in it.'"
32. Muslim:C32B20N4646"Muhammad stood up among his Companions to deliver his sermon in which he told them that Jihad in Allah's Cause and belief in Allah were the most meritorious of acts. A man stood and said: 'Messenger, do you think that if I am killed in the Way of Allah, my sins will be blotted out?' The Messenger said: 'Yes, in case you are killed in Allah's Cause and you always fought facing the enemy, never turning your back upon him.' The man asked (again).' The Messenger said: 'Yes, if you always fought facing the enemy and never retreated. Gabriel has told me this.'"
33. Sahih Bukhari 4:52:105 "The Prophet said, 'If somebody keeps a horse in Allah's Cause motivated by His promise, then he will be rewarded for what the horse has eaten or drunk and for its dung and urine.'"
34. Sahih Muslim 20:4645 "The Prophet said: 'Whoever cheerfully accepts Allah as his Lord, Islam as his Religion and Muhammad as his Apostle is necessarily entitled to enter Paradise.'Abu wondered at it and said: 'Messenger of Allah, repeat that for me.' He did that and said: 'There is another act which elevates the position of a man in Paradise to a grade one hundred (higher), and the elevation between one grade and the other is equal to the height of the heaven from the earth.' Abu said: 'What is that act?' He replied: 'Jihad in the Way of Allah! Jihad in Allah's Cause!'"
35. Sahih Bukhari 4:52:53 "The Prophet said, 'Nobody who dies and finds Paradise would wish to come back to this life even if he were given the whole world and whatever is in it, except the syahids who, on seeing the superiority of syahid, would like to come back to get killed again in Allah's Cause.'"
Qur’an Verses about Jihad 
1. Qur'an 9:88 "The Messenger and those who believe with him, strive hard and struggle with their wealth and lives in Allah's Cause. They are the ones who will have all the goodness, and they are the ones who will prosper"
2. Qur'an 9:111 “Indeed Allah has purchased from the believers their persons and their wealth and in return has promised them paradise; they fight in the cause of Allah and slay and are slain. This is a true promise which is binding on Him mentioned in Torah, the Gospel and the Qur’an; and who is more true in fulfilling his promise than Allah? Rejoice, therefore, in the bargain which you have made, and that is a mighty achievement. "
3. Qur'an 8:39 "O believers, fight them until there is no more mischief and the Deen 4. of Allah (way of life prescribed by Allah) is established completely; but if they do stop 5. from mischief, then surely Allah is observant of all their actions."
6. Qur'an 9:12 "But if they violate their treaty once they have sworn it and insult our Deen, then fight with the ringleaders of the unbelief - for their oaths are nothing to them - so that they may be stopped. Will you not fight against those people who have broken their oaths, conspired to expel the Messenger and were the first to attack you? Do you fear them? Nay, it is Allah Who is more deserving of your fear, if you are true believers. Fight them; Allah will punish them by your hands and humiliate them. He will grant you victory over them and soothe the hearts of a believing people. He will take away all rancor from their hearts. Allah shows mercy to whom He pleases, and Allah is All-Knowledgeable, All-Wise.."
7. Qur'an 9:29 " Fight those people of the Book (Jews and Christians) who do not believe in Allah and the Last Day, do not refrain from what has been prohibited by Allah and His Messenger and do not embrace the religion of truth (Al-Islam), until they pay Jizya (protection tax) with their own hands and feel themselves subdued."
8. Qur'an 8:65 "O Prophet, rouse the believers to fight. If there are twenty among you, patient and persevering, they will vanquish two hundred; if there are a hundred then they will slaughter a thousand unbelievers, for the infidels are a people devoid of understanding."
9. Qur'an 2:217 "They question you concerning fighting in the sacred month. Say: 'fighting therein is a grave (matter); but to prevent access to Allah, to deny Him, to prevent access to the Sacred Mosque, to expel its members, and polytheism are worse than slaughter. Nor will they cease fighting you until they make you renegades from your religion. If any of you turn back and die in unbelief, your works will be lost and you will go to Hell."
10. Qur'an 9:38 "Believers, what is the matter with you, that when you are asked to go forth and struggle in Allah's Cause you cling to the earth? Do you prefer the life of this world to the Hereafter? If it is so, then you should know that the comforts of this life are little compared to the life of the hereafter.."
11. Qur'an 9:123 "O believers! Fight the unbelievers who hem you in, to let them know how strong you are; you should know that Allah is on the side of the Godfearing."
12. Qur'an 8:74-75 "Those who believed (embraced Islam), migrated and made Jihad (exerted their utmost struggle) in the cause of Allah, and those who gave them asylum and help - they are the true believers. They shall have forgiveness and honorable provisions. Those who believed (embraced Islam) afterwards, migrated and joined you in Jihad - they too are your brothers, although according to the Book of Allah the blood relatives have greater rights on one other. Indeed Allah knows everything.”
13. Qur'an 47:31 " We shall put you to test until We know the valiant and the resolute among you, and test all that is said about you."
14. Qur'an 61:2 "O Muslims, why say one thing and do another? Grievously odious and hateful is it in the sight of Allah that you say that which you do not. Truly Allah loves those who Fight in His Cause in a battle array, as if they were a solid cemented structure."
15. Qur'an 4:74 "Let those who struggle in Allah's Cause sell this world's life for the hereafter. To him who fights in Allah's Cause, whether he is slain or victorious, We shall give him a reward."
16. Qur'an 4:75-76 "And what reason do you have not to fight in the cause of Allah, to rescue the helpless oppressed old men, women, and children who are crying: "Our Lord! Deliver us from this town whose people are oppressors; send us a protector by Your grace and send us a helper from Your presence?"  Those who are believers fight in the cause of Allah and those who are unbelievers fight in the cause of Taghut (forces of Satan): so fight against the helpers of Satan; surely, Satan’s crafty schemes are very weak.."
17. Qur'an 4:95 "Not equal are believers who sit home and receive no hurt and those who Fight in Allah's Cause with their wealth and lives. Allah has granted a grade higher to those who Fight with their possessions and bodies to those who sit home. Those who Fight He has distinguished with a special reward."
18. Qur'an 8:15 "Believers, when you meet unbelieving infidels in battle while you are marching for war, never turn your backs to them. If any turns his back on such a day, unless it be in a stratagem of war, a maneuver to rally his side, he draws on himself the wrath of Allah, and his abode is Hell, an evil refuge!"
19. Qur'an 4:95 "Those believers who stay at home [having no physical disability] are not equal to those who make Jihad (struggle) in the cause of Allah with their wealth and their persons. Allah has granted a higher rank to those who make Jihad with their wealth and their persons than to those who stay at home. Though Allah has promised a good reward for all, Allah has prepared a much richer reward for those who make Jihad for Him than for those who stay at home."
21. Qur'an 9:122 "It is not proper that the believers should go forth all together. Therefore, why not a squadron from each division stay behind so that they may obtain the understanding of Deen (Al-Islam), and admonish the people when they return to them so that they may refrain (from doing evil)”
22. Qur'an 047.033 "Believers, obey Allah, and obey the Messenger! Those who disbelieve and hinder men from the Cause of Allah, He will not pardon. Do not falter; become fainthearted, or weak-kneed, crying for peace. You have the upper hand."
23. Qur'an 9:111 "Allah has purchased the believers, their lives and their goods. For them (in return) is the Garden (of Paradise). They Fight in Allah's Cause, and slay others and are slain, they kill and are killed. It is a promise binding on Him in the Taurat (Torah), the Injeel (Gospel), and the Qur'an. And who is more faithful to his covenant than Allah? Then rejoice in the bargain which you have concluded. It is the achievement supreme."
24. Qur'an 61:10 "Believers, shall I lead you to a bargain or trade that will save you from a painful torment? That you believe in Allah and His Messenger (Muhammad), and that you strive and Fight in Allah's Cause with your property and your lives: That will be best for you!"
25. Qur'an 3:156 "If you are slain, or die, in Allah's Cause [as a syahid], pardon from Allah and mercy are far better than all they could amass."
26. Qur'an 3:169 "Think not of those who are slain in Allah's Cause as dead. Nay, they live, finding their provision from their Lord. Jubilant in the bounty provided by Allah: and with regard to those left behind, who have not yet joined them (in their bliss), the syahids in the fact that on them is no fear, nor have they cause to grieve."
27. Qur'an 3:172 "Of those who answered the call of Allah and the Messenger, even after being wounded (in the fight), those who do right and ward off have a great reward."
28. Qur'an 47:4 "But if it had been Allah's will, He Himself could have exacted retribution and punished them (without your help). But He lets you Fight in order to test you. But those who are killed in Allah's Cause, will never let their deeds go to waste."
Islamic Figures quotes about Jihad 
- “Jihad is divided into four branches: to persuade people to be obedient to Allah; to prohibit them from sin and vice; to struggle (in the cause of Allah) sincerely and firmly on all occasions and to detest the vicious. Whoever persuades people to obey the orders of Allah provides strength to the believers; whoever dissuades them from vices and sins humiliates the unbelievers; whoever struggles on all occasions discharges all his obligations and whoever detests the vicious only for the sake of Allah, then Allah will take revenge on his enemies and will be pleased with Him on the Day of Judgment”.
- “Daily prayers are the best medium through which one can Seek the nearness to Allah. Hajj is Jihad for every weak person. For everything that you own there is Zakat, and Zakat of your body is fasting. The Jihad of a woman is to afford pleasant company to her husband.”
- Ali ibn Abi Thalib
- This is a matter of religion, not politics. When a Muslim land is occupied, Jihad becomes an individual duty for every man and woman, boy and girl. A woman goes out to Jihad without her husband's permission and a child without his father's permission.
- The Prophet Muhammad was sent from the beginning as a Mujaheed but he did not start fighting from the beginning, because Jihad does not only mean fighting. Fighting is a part of Jihad.
- "It must now be obvious that the objective of the Islamic jihad is to eliminate the rule of an un-Islamic system, and establish in its place an Islamic system of state rule. Islam does not intend to confine his rule to a single state or a hand full of countries. The aim of Islam is to bring about a universal revolution. Although in the initial stages, it is incumbent upon members of the party of Islam to carry out a revolution in the state system of the countries to which they belong; their ultimate objective is none other than world revolution."
- Sayyid Abul' Ala Mawdudi, Jihad in Islam pp. 20
- "Islam wishes to destroy all states and governments anywhere on the face of the earth which are opposed to the ideology and programme of Islam regardless of the country or the Nation which rules it. The purpose of Islam is to set up a state on the basis of its own ideology and programme, regardless of which nation assumes the role of the standard-bearer of Islam or the rule of which nation is undermined in the process of the establishment of an ideological Islamic State. Islam requires the earth—not just a portion, but the whole planet .... because the entire mankind should benefit from the ideology and welfare programme [of Islam] ... Towards this end, Islam wishes to press into service all forces which can bring about a revolution and a composite term for the use of all these forces is ‘Jihad’. .... the objective of the Islamic ‘ Jihād’ is to eliminate the rule of an un-Islamic system and establish in its stead an Islamic system of state rule."
- Sayyid Abul Ala' Mawdudi, Jihad in Islam Pg. 6-7 and Pg. 22
- “The question is whether aggressive battle is by itself commendable or not. If it is, why should the Muslims stop simply because territorial expansion in these days is regarded as bad? And if it is not commendable, but deplorable, why did Islam not stop it in the past? ... Aggressive Jihad is lawful even today for the purpose it was lawful in those days."
- Muhammad Taqi Usmani, Islam and Modernism Pg. 91
See also 
- The Book of Jihad and Expedition in Sahih Muslim, Book 19
- Jihad is an Integral Part of Islam
- "Jihadist Video Shows Young Boy Beheading Pakistani Man" by Benjamin Sand at Voice of America (23 April 2007)