Quran 3:139 — The Amramites (Ali-'Imran)

You shall not waver, nor shall you grieve, for you are the ultimate victors, if you are believers.

[3:138] This is a proclamation for the people, and a guidance and enlightenment for the righteous.

[3:140] If you suffer hardship, the enemy also suffers the same hardship. We alternate the days of victory and defeat among the people. GOD thus distinguishes the true believers, and blesses some of you with martyrdom. GOD dislikes injustice.