An-Nisa 4:94 يا ايها الذين امنوا اذا ضربتم في سبيل الله فتبينوا ولا تقولوا لمن القى اليكم السلام لست مومنا تبتغون عرض الحياة الدنيا فعند الله مغانم كثيرة كذالك كنتم من قبل فمن الله عليكم فتبينوا ان الله كان بما تعملون خبيرا ٩٤

O you who believe! When you go (to fight) in the Cause of Allâh, verify (the truth), and say not to anyone who greets you (by embracing Islâm): "You are not a believer"; seeking the perishable goods of the worldly life. There are much more profits and booties with Allâh. Even as he is now, so were you yourselves before till Allâh conferred on you His Favours (i.e. guided you to Islâm), therefore, be cautious in discrimination. Allâh is Ever Well-Aware of what you do.