"I do my utmost to lead you in prayer just as I saw the Prophet ﷺ lead us in prayer."Thabit said, "Anas used to do something I do not see you doing. When he raised his head from bowing, he would stand so long that one might say, 'He has forgotten,' and between the two prostrations he would remain so long that one might say, 'He has forgotten.'"
إني لا آلو أن أصلي بكم كما رأيت النبي ﷺ يصلي بنا، قال ثابت: كان أنس يصنع شيئا لم أركم تصنعونه، كان إذا رفع رأسه من الركوع قام حتى يقول القائل: قد نسي، وبين السجدتين حتى يقول القائل: قد نسي.
Bukhari narrated it in the Book of Adhan (821), and Muslim in the Book of Prayer (472), both through the route of Hammad bin Zayd, from Thabit, from Anas, and the wording given here is Bukhari's. In another version with Muslim (473), from Anas, he said, "I have not prayed behind anyone whose prayer was more concise yet complete than the prayer of the Messenger of Allah ﷺ. The prayer of the Messenger of Allah ﷺ was measured, and the prayer of Abu Bakr was measured, but when Umar bin Khattab came, he lengthened the Fajr prayer."The Messenger of Allah ﷺ, when he said, "Sami Allahu liman hamidah" (Allah hears whoever praises Him), would stand until we would say, "He has forgotten," then he would prostrate and sit between the two prostrations until we would say, "He has forgotten."His statement "he has forgotten" means that whatever comes after it is omitted, or it means that he created the impression, in people's minds, that is, in their thinking, that he had left it out.Hafiz bin Qayyim said, "This sunnah was abandoned by most people after the passing of the era of the companions. This is why Thabit said, 'Anas used to do something I do not see you doing, he would linger between the two prostrations...'" See Zad Mad (1/239).I say, this lingering is also established in the hadith of Rifa bin Rafi and others besides him.