Jabir ibn 'Abdullah · The Book of the Commencement of the Prayer

The Messenger of Allah (ﷺ) used to pause briefly when he had started to pray.

"I have never prayed behind anyone whose prayer more closely resembled that of the Messenger of Allah (ﷺ) than so-and-so." (The narrator) Sulaiman siad: "He used to make the first two rak'ahs of Zuhr lengthy and the last two shorter, and he would make 'Asr shorter; in Maghrib he would recite the short Mufassal surahs, in Isha' the medium-length Mufassal surahs and in Subh the long Mufassal surahs.

A man heard another man reciting "Say: He is Allah, (the) One" and repeating it. When morning came he went to the Messenger of Allah (ﷺ) and told him about that. The Messenger of Allah (ﷺ) said: "By the One in Whose Hand is my soul, it is equal to one-third of the Quran."

The Prophet (ﷺ) said: "Say: He is Allah, (the) One" is one-third of the Quran."