How the Prophet received the Revelation
This is Allah teaching to His Messenger that how to receive the revelation from the angel. For verily, he (the Prophet) was rushing in his attempts to grasp the revelation and he would be reciting the revelation with the angel while he was reciting it. Therefore, Allah commanded him that when the angel brings some revelation to him he should just listen. Allah would make sure to collect it in his chest, and He would make it easy for him to recite it in the same way that it was revealed to him. Allah would explain it, interpret it and clarify it for him. So
the first phase was gathering it in his chest,
the second phase was recitation and
the third phase was its explanation and clarification of its meaning.
Thus, Allah says,
لَاا تُحَرِّكْ بِهِ لِسَانَكَ لِتَعْجَلَ بِهِ
Move not your tongue concerning to make haste therewith.
meaning, with the Qur'an.
This is as Allah says,
وَلَا تَعْجَلْ بِالْقُرْءانِ مِن قَبْلِ إَن يُقْضَى إِلَيْكَ وَحْيُهُ وَقُل رَّبِّ زِدْنِى عِلْماً
And be not in haste with the Qur'an before its revelation is completed to you, and say;
"My Lord! Increase me in knowledge." (20;114)
Then Allah says