I offered Salat (Tahajjud - optional night prayer) with the Prophet (ﷺ) one night, and he started reciting (Surat) Al-Baqarah. I thought that he would bow at the end of one hundred Verses, but he continued reciting; I, then, thought that he would perhaps recite the whole (Surah) in a Rak'ah, but he proceeded on, and I thought he would perhaps bow on completing (this Surah); he then started (reciting Surat) An-Nisa'; he then started (Surat) Al-'Imran and his recitation was unhurried. And when he recited the Verses which referred to the Glory of Allah, he glorified Him (by saying Subhan Allah - My Rubb, the Supreme is far removed from every imperfection), the Great, and when he recited the Verses that mention supplication, he supplicated, and when he recited the Verses that mention seeking Refuge of the Rubb, he sought (His) Refuge. Then he bowed and said: "My Rubb, the Supreme is far removed from every imperfection (Subhana Rabbiyal-Azim);" his bowing lasted about the same length of time as his standing (and then on returning to the standing posture after Ruku') he said: "Allah listened to him who praised Him (Sami' Allahu liman hamidah, Rabbana wa lakal hamd)." Then he stood about the same length of time as he had spent in bowing. He then prostrated himself and said: "My Rubb, the Supreme is far removed from every imperfection (Subhana Rabbiyal-A'la)," and his prostration lasted nearly the same length of time as his standing.

[Muslim].