And do not make your oaths a means of deceit between you, lest a foot should slip after its stability and you should taste evil because you turned away from Allah's way and grievous punishment be your (lot).

And what reason have you that you should not spend in Allah's way? And Allah's is the inheritance of the heavens and the earth, not alike among you are those who spent before the victory and fought (and those who did not): they are more exalted in rank than those who spent and fought afterwards; and Allah has promised good to all; and Allah is Aware of what you do.