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 NOW [as for thee, O Muhammad,] thou wert not present on the sunset slope [of Mount Sinai] when We imposed the Law upon Moses, nor wert thou among those who witnessed [his times]: 44 We brought into being many generations who lived long lives, nor did you live among the people of Midian and recite our revelations to them, it is We who send messengers, 45 Nor wast thou at the side of (the Mountain of) Tur when we called (to Moses). Yet (art thou sent) as Mercy from thy Lord, to give warning to a people to whom no warner had come before thee: in order that they may receive admonition. 46 And in case disaster comes upon them for what they have done themselves, they should say: "O Lord, why did You not send an apostle to us that we should have followed Your commands, and been with those who are believers;" 47 But when there came unto them the Truth from Our presence, they said: Why is he not given the like of what was given unto Moses? Did they not disbelieve in that which was given unto Moses of old? They say: Two magics that support each other; and they say: Lo! in both we are disbelievers. 48 Say: 'If what you say is true, bring down from Allah a Book that is a better guidance than both, I will follow it' 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