So when you meet in battle those who disbelieve, then smite the necks until when you have overcome them, then make (them) prisoners, and afterwards either set them free as a favor or let them ransom (themselves) until the war terminates. That (shall be so); and if Allah had pleased He would certainly have exacted what is due from them, but that He may try some of you by means of others; and (as for) those who are killed in the way of Allah, He will by no means allow their deeds to perish.
Meaning:-
Smite: to strike
Perish: disappear, vanish,