Sayyiduna Qays bin Mas'ud (may Allah be pleased with him) reports from his father that he was with Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) in Kufah. Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) saw the people standing, waiting for the funeral bier to be set down, so Sayyiduna Ali (may Allah be pleased with him) signalled to them with his whip to sit, and said: "The Messenger of Allah (peace and blessings be upon him) also used to stand, and then he sat."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجنائز / 6888