فَإِذَا قَرَأْنَـٰهُ فَٱتَّبِعْ قُرْءَانَهُۥ
Fa izaa qaraanaahu fattabi' qur aanah
So when we have recited it, follow its recitation.
The recitation is claimed in the divine plural, though the voice the Prophet heard was the angel's, and commentators took this to mean the messenger's reading counts as the sender's own. Ittibāʿ, following, was glossed two ways: Ibn ʿAbbas read it as listening in silence while the recitation is delivered, and Qatada as following what the recitation permits and forbids. The first reading keeps the passage inside the moment of revelation, and the second extends it to every later reader.