صحیح ابن حبان
Ibn Hibban
كتاب البر والإحسان
Book of Righteousness and Goodness
باب الصحبة والمجالسة - ذكر البيان بأن تفرق القوم عن المجلس عن غير ذكر الله والصلاة على النبي صلى الله عليه وسلم يكون حسرة عليهم في القيامة
Chapter on Companionship and Sitting – Clarification that leaving a gathering without mentioning Allah or sending blessings on the Prophet will be a regret on the Day of Judgment
1 hadith
Hadith 590
Sayyiduna Abu Huraira (may Allah be pleased with him) narrates: The Prophet Muhammad (peace and blessings be upon him) said: "When some people gather in an assembly, and then disperse from that assembly without remembering Allah and without sending blessings upon the Prophet Muhammad (peace and blessings be upon him), then this will be a cause of regret for them on the Day of Resurrection."