Ibn Abbas reported with regard to the words:
Do not move thy tongue there with to make haste, that the Messenger of Allah ( صلی اللہ علیہ وسلم ) felt it hard and he moved his lips. Ibn 'Abbas said to me (Sa'id b. Jubair): I move them just as the Messenger of Allah ( صلی اللہ علیہ وسلم ) moved them. Then said Sa'id: I move them just as Ibn 'Abbas moved them, and he moved his lips. Allah, the Exalted, revealed this: Do not move your tongue therewith to make haste. It is with US that its collection rests and its recital (al-Qur'an, ixxv. 16). He said: Its preservation in your heart and then your recital. So when We recite it, follow its recital. He said: Listen to it, and be silent and then it rests with Us that you recite it. So when Gabriel came to the Messenger of Allah ( صلی اللہ علیہ وسلم ), he listened to him attentively, and when Gabriel went away, the Messenger of Allah ( صلی اللہ علیہ وسلم ) recited as he (Gabriel) had recited it.