Silsilah as-Sahihah 3158 — Remember Allah when rising, sitting

It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "There is no group of people who sit in a gathering in which Allah is not mentioned, except that they will consider that sitting a regret on the Day of Resurrection."