“Not equal are those believers who sit (at home) and receive no hurt, and those who strive and fight in the cause of God with their goods and their persons. God hath granted a grade higher to those who strive and fight with their goods and persons than to those who sit (at home). Unto all (in Faith) Hath God promised good: But those who strive and fight Hath He distinguished above those who sit (at home) by a special reward” – Quran 4:95
The above Quranic verse urges (sanctions) Muslims to ‘fight in the cause of God’. Fighting in the cause of God, does not mean killing of civilians. Muslims are told in the passage to fight oppression, practiced against them or against others (i.e., non-Muslims). The objective of Jihad (‘Fighting in the cause of God’) is to protect religious freedom for all. The following Quranic passage proves what the meaning for ‘fight in the cause of God’ means,
And what is [the matter] with you that you fight not in the cause of God and [for] the oppressed among men, women, and children who say, “Our Lord, take us out of this city of oppressive people and appoint for us from Yourself a protector and appoint for us from Yourself a helper?” – Quran 4:75
The above verse makes it evident that fighting in the cause of God is to free people from oppression, persecution from tyrants. Quranic verse 4:95, Allah says, how can those who fight and those who do nothing be the same level (in reward) in the sight of Him? Of course they’re not equal! Those who fought and helped the oppressed will get reward from their Lord.
Witnesses to Faith? – Martyrdom in Christianity and Islam Brian Wicker
“The prophet is instructed only to ‘urge on the believers’ (4:64). The Qur’an – and the Hadith at greater length – urge the Muslim fighters (those who are defending themselves or the oppressed) in the strongest way, by showing the just cause, showing the bad conduct of the enemy and promising great rewards in the afterlife for those who make such sacrifices.
The exhortations in the Qur’an to Muslims to fight ‘in the cause of God’ (for example, 4:95) also bear witness that not everyone actually did so. Even when some Muslims ‘turned back’ at the Battle of Uhud, in a premature bid to take booty, so causing the Muslims to lose the battle, the Qur’an endorses the ‘lenient’ attitude of the Prophet (pbuh) towards them (3:159).” 
Dr. Ingrid Mattson
It is in this context that the Qur’an asserts the superiority of those who are willing to sacrifice for the good of the community by offering themselves for military service (the Mujahid/Mujahidun):
That the Medinan revelations pay significant attention to situations of conflict is not surprising, given that the Muslim community was engaged in numerous battles during this period. Military force was used to secure the Medinan City-State, to protect its citizens and allies, to ensure the viability of trade, to recover property unjustly confiscated from the Muhajirun, and finally, to overthrow the Meccan regime. In the Battles of Badr,
Uhud, Khandaq, and in other smaller skirmishes, many Muslims (and some of their non-Muslim allies) lost their lives. The Qur’an reassures the community that such sacrifice, when made for just cause, is one of the highest forms of witnessing to one’s belief’s. Although he or she has lost his or her life, the believer who dies fighting for righteous cause gains eternal life in the presence of God… 
Classical scholar Imam Fakhr al-Din al-Razi (1149 – 1210) writes in his Tafsir al Kabir on Quran 4:95,
“The Shi’ah say: This ayah proves that Ali bin abi Talib is superior to Abu Bakr, and that is because Ali waged more jihad. So the proportion in which there appears to be a difference in the matter is Abu Bakr was from those who sit back (more) and Ali was from those who stand (to fight more). If it was like that, then it would be necessary that Ali be superior to him due to His Saying,
Allah has preferred those who strive over those who sit back with a tremendous reward.So it is said to them (the Shi’ah): Certainly, the undertaking (of jihad) of Ali was more than the undertaking of Rasulullah. For that, you must impose the same rule of this ayah that Ali be superior to Rasulullâh.
No intelligent person says this. So if you say: Certainly, the mujahadah of Rasulullah with the kuffar was greater than the mujahadah of Ali with them, because Rasulullah strove against the kuffar with establishment of proofs, proclamation, and eliminating doubt and misguidance. So this jihad is more complete than that jihad. So we say: all of you accept from us his example in the right of Abu Bakr.
That is because when Abu Bakr embraced Islam in the earliest (period of nubuwwah), he was occupied in (bringing) Islam to all the people until ‘Uthmân bin Affan, Talha, Zubair, Sa’d bin abi Waqqas and ‘Uthman bin Madh’un embraced Islam at his hands.
He would overdo (himself) in encouraging the people in iman (faith) and in the protection of Muhammad with his own self and wealth. Ali during that time was a child. No one embraced Islam from his words and he was not able to protect Muhammad. So the jihad of Abu Bakr was superior to the jihad of Ali from two aspects.
First: That the jihad of Abu Bakr was during the the first period (of nubuwwah) when Islam was at the point of weakness. As for Ali, it only became apparent in Madinah in battles. Islam during that time was strong.
Second: That the jihad of Abu Bakr was by da’wah to Din (religion) and most of those major sahabah (of the ten who were promised jannah) embraced Islam at his hands. This kind of jihad is the occupation of the Nabi. As for the jihad of Ali, then it was by fighting. And there is no doubt that the first is superior than the other.” (Tafsir al-Kabir lir-Razi, by Imam Fakhr al-Din al-Razi, volume 11, page 10, online source,
 Witnesses to Faith? – Martyrdom in Christianity and Islam Brian Wicker page 158
 The Story of the Qur’an: Its History and Place in Muslim Life By Ingrid Mattson