Tafsir of Al-Isra 17:105

{And with the truth We have sent it down, and with the truth it has descended}

We have not sent down the Qur’an except with the wisdom that necessitates its revelation, and it has not descended except accompanied by truth and wisdom, as it contains guidance to every good.

Alternatively, it means: We did not send it down from the heaven except with the truth, protected by the surveillance of the angels; and it did not descend upon the Messenger except protected by them from the interference of the devils.

{And We have not sent you}

Except to give them glad tidings of Paradise and to warn them of the Fire. There is nothing beyond that for you, such as compelling them to accept the religion or anything similar.

{And [it is] a Qur’an which We have separated [by intervals] that you might recite it to the people over a prolonged period, and We have sent it down progressively}