Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "When some people sit in a gathering and do not remember Allah in that gathering, nor send blessings upon the Prophet (peace and blessings be upon him), it will be a cause of regret for them on the Day of Resurrection with regard to the reward, even if they enter Paradise."
(Allamah Haythami says:) I say: Tirmidhi recorded this report in abridged form.
Ahmad recorded it, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الأذكار / 16786
Hadith Gradingمحدثین:إسنادہ صحیح
Hadith Takhrij«اخرجه احمد فى المسند (463/2) ، أخرجه سنن الترمذي برقم: 3380، وأخرجه سنن أبي داود برقم: 5059، وأخرجه مسند أحمد برقم: 9649، وأخرجه المستدرك على الصحيحين برقم: 1853»