After We had destroyed the earlier generations We bestowed the Book on Moses - a source of enlightenment for people and a guidance and mercy -- that they may take heed. 43 And you, [O Muhammad], were not on the western side [of the mount] when We revealed to Moses the command, and you were not among the witnesses [to that]. 44 But We brought forth generations, and their lives dragged on for them. And thou wast not a dweller in Midian, reciting unto them Our revelations, but We kept sending (messengers to men). 45 you were not on the side of the Mount when We called out to Moses, but We have sent you as a mercy from your Lord, so that you may warn people to whom no warner has been sent before you, so that they may take heed, 46 If (We had) not (sent thee to the Quraish),- in case a calamity should seize them for (the deeds) that their hands have sent forth, they might say: "Our Lord! why didst Thou not sent us a messenger? We should then have followed Thy Signs and been amongst those who believe!" 47 But (now), when the Truth has come to them from Ourselves, they say, "Why are not (Signs) sent to him, like those which were sent to Moses?" Do they not then reject (the Signs) which were formerly sent to Moses? They say: "Two kinds of sorcery, each assisting the other!" And they say: "For us, we reject all (such things)!" 48 Say: "Then bring a Book from God which gives better guidance than these so that I may follow it, if you speak the truth." 49 So if they do not accept your challenge, then know that they only follow their desires; and who is more astray than one who follows his desires away from the guidance of Allah? Indeed Allah does not guide the unjust. 50