It is narrated from Sayyiduna Ibn Amr, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: "Those people who sit in a gathering and do not remember Allah in it, on the Day of Resurrection they will feel regret and sorrow over it."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 7093
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد حسن على خطأ فى تسمية صحابيه.