We indeed sent many Messengers before you and We gave them wives and children; and no Messenger had the power to produce a miraculous sign except by the command of Allah. Every age has its own (revealed) Book. 38 God annuls or confirms whatever He wills [of His earlier messages] - for with Him is the source of all revelation. 39 Whether We show you part of what We have promised them or cause you to pass away [before that], your mission is only to give warning; it is for Us to do the reckoning. 40 See they not how we aim to the land, reducing it of its outlying parts? (When) Allah doometh there is none that can postpone His doom, and He is swift at reckoning. 41 Those who lived before them also devised many a plot, but the master plot rests with Allah. He knows what everyone does. The deniers of the truth will soon come to know whose end is good. 42 The unbelievers say, 'Thou art not an Envoy.' Say: 'God suffices as a witness between me and you, and whosoever possesses knowledge of the Book.' 43