Rules of War*
[2:190] You may fight in the cause of GOD against those who attack you, but do not aggress. GOD does not love the aggressors.
*2:190 All fighting is regulated by the basic rule in 60:8-9. Fighting is allowed strictly in self-defense, while aggression and oppression are strongly condemned throughout the Quran.
[2:191] You may kill those who wage war against you, and you may evict them whence they evicted you. Oppression is worse than murder. Do not fight them at the Sacred Masjid, unless they attack you therein. If they attack you, you may kill them. This is the just retribution for those disbelievers.
[2:192] If they refrain, then GOD is Forgiver, Most Merciful.
[2:193] You may also fight them to eliminate oppression, and to worship GOD freely. If they refrain, you shall not aggress; aggression is permitted only against the aggressors.
[2:194] During the Sacred Months, aggression may be met by an equivalent response. If they attack you, you may retaliate by inflicting an equitable retribution. You shall observe GOD and know that GOD is with the righteous.
[2:195] You shall spend in the cause of GOD; do not throw yourselves with your own hands into destruction. You shall be charitable; GOD loves the charitable.
Grossness of Murder
[5:32] Because of this, we decreed for the Children of Israel that anyone who murders any person who had not committed murder or horrendous crimes, it shall be as if he murdered all the people. And anyone who spares a life, it shall be as if he spared the lives of all the people. Our messengers went to them with clear proofs and revelations, but most of them, after all this, are still transgressing.
A Higher Call
Think about your family; your parents, brothers, sisters, cousins, aunts, uncles, grandparents, great grandparents. How far and how wide can you go in your family tree? We all originate from the same mom and dad (7:189) and God made us into distinct people that we may recognize one another (29:13). We are all related in one way or another and we should never cease from holding out showing compassion to our family. When we spare a life, save a life, affect a life we are not only affecting that one life, but all the lives that will descend from that individual.
Family Tree Explained