Therefore , when ye meet the Unbelievers ( in fight ) , smite at their necks ; At length , when ye have thoroughly subdued them , bind a bond firmly ( on them ) : thereafter ( is the time for ) either generosity or ransom : Until the war lays down its burdens . Thus ( are ye commanded ) : but if it had been Allah 's Will , He could certainly have exacted retribution from them ( Himself ) ; but ( He lets you fight ) in order to test you , some with others .