O Believers! When you set out (to fight) in the way of Allah, carry out a careful probe and do not say to him who greets you (as a Muslim): ‘You are not a believer.’ You seek goods of worldly life (in the shape of spoils of war, after killing a Muslim declaring him a disbeliever). So, (rest assured that) Allah has gains and booties in plenty. Before this you (too) were the same. Then Allah conferred on you His Favour (and you became Muslims). So investigate and confirm the truth (about others as well). Surely, Allah is Well Aware of what you do.