“When the Quran was being revealed to the Messenger of Allah, he would move his tongue in attempt to memorize it. So Allah, Blessed is He and Most High, revealed: Move not your tongue concerning it to make haste therewith.” He said: “So he would move his two lips.” And Sufyan (a sub-narrator) would move his two lips.
كَانَ رَسُولُ اللَّهِ ﷺ إِذَا أُنْزِلَ عَلَيْهِ الْقُرْآنُ يُحَرِّكُ بِهِ لِسَانَهُ يُرِيدُ أَنْ يَحْفَظَهُ فَأَنْزَلَ اللَّهُ ( لا تُحَرِّكْ بِهِ لِسَانَكَ لِتَعْجَلَ بِهِ ) قَالَ فَكَانَ يُحَرِّكُ بِهِ شَفَتَيْهِ وَحَرَّكَ سُفْيَانُ شَفَتَيْهِ