Al-Matalib al-'Aliyah 578 — Tahajjud

It is narrated from Sayyiduna Hudhayfah (may Allah be pleased with him) that he said: "One night I came to the Messenger of Allah (peace and blessings be upon him) in order to pray behind him (peace and blessings be upon him). He (peace and blessings be upon him) began the prayer and recited in a way that was neither very short and quick nor very loud; rather, it was an excellent and beautiful recitation in which he (peace and blessings be upon him) recited slowly with tartil, pausing, and letting us hear. The narrator says: Then he (peace and blessings be upon him) bowed for about the length of a long surah, then raised his blessed head and said these words: 'Sami'a Allahu liman hamidah, dhu al-jabaruti wa al-malakuti wa al-kibriya'i wa al-'azamah' (Allah has heard the one who praised Him; He is the Possessor of Jabarut (utmost dominance and power), the Possessor of Malakut (true sovereignty), and the Possessor of grandeur and majesty). The narrator relates that then his (peace and blessings be upon him) standing (after the bowing) was also about as long as a surah, and he (peace and blessings be upon him) prostrated for a similar length, until he (peace and blessings be upon him) finished reciting the long surahs while part of the darkness of the night still remained."
Abd al-Malik says that this was the voluntary night prayer (tahajjud).