Majma al-Zawaid — Hadith 14453

Al-Hasan narrates: Sayyiduna Uthman bin Abi al-As (may Allah be pleased with him) married one of the wives (that is, a widow or divorcee) of Sayyiduna Umar bin al-Khattab (may Allah be pleased with him). He said: By Allah! When I married this woman, I did not do so out of desire for wealth or children; rather, I wanted her to tell me about the night routine of Sayyiduna Umar (may Allah be pleased with him). He asked the woman how Sayyiduna Umar (may Allah be pleased with him) used to offer his voluntary prayers at night. She said: He would offer the Isha prayer, then instruct us to place a vessel of water at his head, which we would cover. He would wake at some point in the night, put his hand into the water, wipe his face and both hands with the water, then remember Allah as much as Allah willed. He would wake several times in the night and do this, until the time came at which he would stand to offer his voluntary prayers. A narrator named Ibn Buraydah says: I asked my teacher: Who narrated this hadith to you? He replied: The daughter of Sayyiduna Uthman bin Abi al-As (may Allah be pleased with him) narrated this hadith to me. He said: Then she is thiqah (trustworthy).
Imam al-Tabarani recorded it, and its narrators are thiqat (trustworthy).