He reported God's messenger as saying, "If people sit in an assembly in which they do not remember God or invoke a blessing on their Prophet, vengeance will descend upon them. If God will He will punish them, but if He wills He will forgive them.” Tirmidhi transmitted it.
Reported by At-Tirmidhi (No. 3380) and Ahmad (No. 9466, 9854, 9888). Cited in Mishkat al-Masabih (No. 2274).
"No people sit in a gathering in which they do not remember Allah and do not invoke blessings upon their Prophet, except that it will be a source of regret for them. If He wills, He will punish them, and if He wills, He will forgive them."
وعنه عن النبي صلى الله عليه وسلم قال: "ما جلس قوم مجلساً لم يذكروا الله تعالى فيه، ولم يصلوا على نبيهم فيه، إلا كان عليهم ترة؛ فإن شاء عذبهم، وإن شاء غفر لهم" ((رَوَاهُ التِّرمِذِيُّ وَقَالَ: "حَدِيثٌ حَسَنٌ")).