It was narrated that Ibn 'Abbas said, concerning the verse

"Move not your tongue concerning (the Qur'an, O Muhammad) to make haste therewith" (al-Qiyamah 75:16): The Prophet (ﷺ) experienced some hardship when the Revelation came to him, and he used to move his lips. Ibn 'Abbas said to me: I will move my lips for you as the Messenger of Allah (ﷺ) used to move his lips. Sa’eed said to me: I will move my lips for you as Ibn 'Abbas moved his lips. Then Allah revealed the verse, “Move not your tongue concerning (the Qur'an, O Muhammad) to make haste therewith. It is for Us to collect it and to give you (O Muhammad (ﷺ)) the ability to recite it (the Qur'an)" (al-Qiyamah 75:16,17), meaning, I will collect (preserve) it in your heart, then you will be able to recite it. “And when We have recited it to you (O Muhammad through Jibreel (Gabriel)), then follow its (the Qur'an's) recitation” i.e., so listen to it attentively. "Then it is for Us (Allah) to make it clear (to you)" (al-Qiyamah 75:19). Then after that, when Jibreel left, he would recite it as it had been recited to him.