It was narrated that Ibn Abbas said:

Concerning the saying of Allah, the Mighty and Sublime: "Move not your tongue concerning to make haste therewith. It is for Us to collect it and to give you the ability to recite it- "The Prophet ﷺ used to suffer a great deal of hardship when the Revelation came to him, and he used to move his lips. Allah said: Move not your tongue concerning to make haste therewith. It is for Us to collect it and to give you the ability to recite it." He said: " (This means) He will gather it in your heart, then you will recite it," And when We have recited it to you, then follow the recitation. He said: "So listen to it and remain silent. So when Jibril came to him, the Messenger of Allah ﷺ listened, and when he left, he would recite it as he had taught him."

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا أَبُو عَوَانَةَ، عَنْ مُوسَى بْنِ أَبِي عَائِشَةَ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ، عَنِ ابْنِ عَبَّاسٍ، فِي قَوْلِهِ عَزَّ وَجَلَّ { لاَ تُحَرِّكْ بِهِ لِسَانَكَ لِتَعْجَلَ بِهِ * إِنَّ عَلَيْنَا جَمْعَهُ وَقُرْآنَهُ } قَالَ كَانَ النَّبِيُّ ﷺ يُعَالِجُ مِنَ التَّنْزِيلِ شِدَّةً وَكَانَ يُحَرِّكُ شَفَتَيْهِ قَالَ اللَّهُ عَزَّ وَجَلَّ { لاَ تُحَرِّكْ بِهِ لِسَانَكَ لِتَعْجَلَ بِهِ * إِنَّ عَلَيْنَا جَمْعَهُ وَقُرْآنَهُ } قَالَ جَمْعَهُ فِي صَدْرِكَ ثُمَّ تَقْرَأَهُ { فَإِذَا قَرَأْنَاهُ فَاتَّبِعْ قُرْآنَهُ } قَالَ فَاسْتَمِعْ لَهُ وَأَنْصِتْ فَكَانَ رَسُولُ اللَّهِ ﷺ إِذَا أَتَاهُ جِبْرِيلُ اسْتَمَعَ فَإِذَا انْطَلَقَ قَرَأَهُ كَمَا أَقْرَأَهُ .