Overall meaning : The Almighty says: After We had destroyed and eradicated the earlier generations that denied their messengers, We gave Moses the Torah as enlightenment to the Children of Israel, and as guidance and mercy for them, so that they might reflect and pay heed. You, Muhammad, were not present on the western side of the mountain when We spoke to Moses and gave him the command to deliver Our message to Pharaoh and his people, nor did you witness what happened there. But between you and them We raised many generations after Moses, and the period of cessation of revelation was so long that the covenants made with Allah were forgotten, and then We sent you, Muhammad, as a messenger to mankind and revealed to you the story of Moses and others.
You did not dwell among the people of Midian, so that you recount to the people of Makkah what happened to them with Moses and what he did there. This did not happen, but We sent you forth as a messenger and revealed to you the Qur’an with such information; otherwise, you would not have known about it.
Nor were present on the side of the mountain when We spoke to Moses and revealed Our will to Him, yet We have revealed to you what happened there, as a mercy from Us to warn your people to whom no messenger has come before, so that they may reflect, take heed and turn to Allah.