Hadith on Revelation Narrated Sa`id bin Jubair

Narrated Sa`id bin Jubair: Ibn `Abbas in the explanation of
the Statement of Allah 'Move not your tongue concerning (the
Qur'an) to make haste therewith (75.16)' said "Allah's Apostle
used to bear the revelation with great trouble and used to
move his lips (quickly) with the Inspiration." Ibn `Abbas
moved his lips saying, "I am moving my lips in front of you as
Allah's Apostle used to move his." Sa`id moved his lips
saying: "I am moving my lips, as I saw Ibn `Abbas moving his."
Ibn `Abbas added, "So Allah revealed 'Move not your tongue
concerning (the Qur'an) to make haste therewith. It is for us
to collect it and to give you (O Muhammad) the ability to
recite it (the Qur'an) (75.16−17)' which means that Allah will
make him (the Prophet ) remember the portion of the Qur'an
which was revealed at that time by heart and recite it. The
Statement of Allah: And 'When we have recited it to you (O
Muhammad through Gabriel) then you follow its (Qur'an)
recital' (75.18) means 'listen to it and be silent.' Then it
is for Us (Allah) to make It clear to you' (75.19) means 'Then
it is (for Allah) to make you recite it (and its meaning will
be clear by itself through your tongue). Afterwards, Allah's
Apostle used to listen to Gabriel whenever he came and after
his departure he used to recite it as Gabriel had recited it."
Sahi Bukhari 1.4