Musannaf Ibn Abi Shaybah 5302 — The imam giving the salam when he sits

Abu Nadrah said: Sayyiduna Uthman (may Allah be pleased with him) had grown old; when he ascended the minbar he would give the greeting (salam), then he would remain (there) for as long as it takes a person to recite Umm al-Kitab (Surah al-Fatihah).