Translation:

105. We sent down the (Qur'an) in Truth and in Truth has it descended: and We sent thee but to give Glad Tidings and to warn (sinners).

Notes (Tafseer)

2315. The Qur-an was sent down by Allah in Truth: it was not forged by any mortal. It has descended in Truth: it was not and has not been falsified or corrupted in the process of being communicated to mankind.

2316. The part of the Prophet was that of a Messenger: he was not responsible if the ungodly rejected it. He fulfilled his mission in promulgating and explaining it and leaving it as a legacy to the world.