O You who have chosen to be graced with belief! When you go forth in the Cause of Allah (to meet the armed challenge), use your discernment. And do not say, out of a desire for the fleeting gains of this worldly life, to anyone who offers you the greeting of peace, "You are not a believer." For with Allah are abundant gains. Remember, once you were ignorant, and you were weak like the disbelievers are now. Allah has been Gracious to you, so be gracious to His servants (9:128), (90:17). Use your discernment. Allah is always Aware of what you do.