The Holy verse says:
"O ye who believe! Shall I show you a commerce that will save you from a painful doom? Ye should believe in Allah and His messenger, and should strive for the cause of Allah with your wealth and your lives. That is better for you, if ye did but know. He will forgive you your sins and bring you into Gardens underneath which rivers flow, and pleasant dwellings in Gardens of Eden. That is the supreme triumph. And (He will give you) another blessing which ye love: help from Allah and present victory. Give good tidings (O Muhammad) to believers. O ye who believe! Be Allah's helpers, even as Jesus son of Mary said unto the disciples: Who are my helpers for Allah? They said: We are Allah's helpers. And a party of the Children of Israel believed, while a party disbelieved. Then We strengthened those who believed against their foe, and they became the uppermost." (61:10-14)
These verses have a story which is:
A man called Ossman Ibn Mzoun, may Allah be pleased with him, who came to Prophet Muhammad, peace and blessings be upon him, and declared that he would divorce his wife, have vasectomy (to stop sexual desire), never eat meat (no luxury food), never sleep at night (to pray), never eat in mornings (fast everyday from sunrise till sunset).
Prophet Mohammed, peace and blessings be upon him, refused this kind of behaviour because Islam wants the Muslim to enjoy life but within the borders that Islam created to guarantee peaceful co-existence between people, so our noble Prophet said: "What is the matter with people who say such and such? But I pray and I sleep, I fast and I break my fast, and I marry women. Whoever turns away from my Sunnah (way) is not of me."
(Sunan an-Nasa'i 3217- Book 26, Hadith 22).
This man then asked about what are the best things that he can do to please GOD then the above verses were revealed.
Notice the following about the above verses:
1- GOD says: "strive" NOT "fight" and mentioned "wealth" before "lives" because this is the case that exposes hypocrites. In English they say: "A friend in need is a friend indeed" because the cases of need are the ones where sincerity or hypocrisy shows best, your friend is still your friend whether you are in need or not, but the case that truly reflects his inner feelings are the times of need. That is the same concept used in the above verses. True belief is shown beyond doubt in cases of need which involves wealth (like giving obligatory charity i.e. zakat) and in case of war. That is when a true believer shines and the hypocrite is exposed, that is why the verse stresses on these two conditions.
2- "wealth" is mentioned before "lives" because (as we have previously explained) striving for the cause of Allah does not mean "fighting" it means striving in numerous ways the most important of which is striving against your own desires to make them all limited to be within the borders set by Islam. "wealth" came first because in Islam there is the obligatory charity (zakat), this is obligatory on every capable Muslim and that is the first point where hypocrisy shows.
3- Notice the verse "And (He will give you) another blessing which ye love: help from Allah and present victory. Give good tidings" (61:13). There are two explanations for this verse that the victory this verse implies is the victory in Mecca, where Muslims were oppressed, prosecuted and tortured and finally had to emigrate secretly to Medina leaving most of their belongings and wealth in Mecca. So GOD in this verse is giving them the good tidings of victory in Mecca. Other scholars say it is the victory over the Romans and the Persians who were the strongest military forces at that age. Later Muslims succeeded in Mecca and were victorious over the Romans and the Persians.
4- Notice the rest of the verse that narrates the story of the "Children of Israel" who, when asked by Prophet Issa (Jesus), peace and blessings be upon him, who were ready to help him, they were divided into two categories, those who decided to stay with him and those who did not, so the verse says : "Then We strengthened those who believed against their foe, and they became the uppermost.", So GOD is telling us that HE supported those who believed from the children of Israel so that they were victorious against those who did not believe...what does that tell you...The Holy Quran declares the fact the GOD supports the believers, whether Muslims, Jews..etc., as long as they believe. HE did not say the Muslims are the only ones who have HIS support, HE says that believers has his support...
How can that be violent if It says that GOD made the believers, whether Muslims or not, victorious...does that promote violence against others or is it declaring that HIS support, and hence undeniable victory, goes to those who believe in HIM, whether Muslims or other.
This proves a major point that "Fighting" in Islam is not a "fight" to impose Islam on people, but rather a defensive war, because victory is granted to the true believers in GOD whether Muslims or not.