Only Fight those who Fight you, and There is to be No Aggression Except Against the Wrongdoers

So if they Remove themselves from you and do Not Fight you and Offer you Peace, then God has Not Made a Cause for you for Fighting Against them

22:39, Qur'an
Permission [to fight] has been given to those who are being fought, because they were wronged.  And indeed, God is Powerful to give them help.

42:39, Qur'an
And [thus there is no cause for blame for] those who, when tyranny strikes them, they defend themselves -

2:190, Qur'an
[But only] fight in the way of God those who fight you [and] do not transgress.  Indeed, God does not love the transgressors.

2:192 - 193, Qur’an
[So] if they cease [fighting], then indeed, God is Forgiving and Merciful.
[So] fight them until there is no [more] oppression and [until] the religion is for God. But if they cease [fighting], then there is to be no aggression except against the wrongdoers.

4:90, Qur'an
[So fight] except for those [disbelievers] who take refuge with a people between yourselves and with whom is a treaty or those who come to you, their hearts strained at [the prospect of] fighting you or fighting their own people.  And if God had willed, He could have given them power over you, and they would have surely fought you.  So if they remove themselves from you and do not fight you and offer you peace, then God has not made a cause for you [for fighting] against them.

4:91, Qur’an
[But] you will find others who wish to obtain security from you and [to] obtain security from their people. Every time they are returned to the temptation [of disbelief], they fall back into it.  So if they do not withdraw from you or offer you peace or restrain their hands, then seize them and kill them wherever you overtake them. And those - We have made a clear authorization for you against them.

4:94, Qur'an
[So] O you who have believed, when you set forth [to fight] in the way of God, investigate; and do not say to one who offers you peace, "You are not a believer," aspiring for the goods of worldly life; for many spoils of war are with God.  You were like that before; then God conferred His favor upon you, so investigate. Indeed God is Aware of what you do.