Hadith 518050
Chapter 56: Speech - كتاب الكلام
وَحَدَّثَنِي مَالِكٌ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ، أَنَّ عُمَرَ بْنَ الْخَطَّابِ، دَخَلَ عَلَى أَبِي بَكْرٍ الصِّدِّيقِ وَهُوَ يَجْبِذُ لِسَانَهُ فَقَالَ لَهُ عُمَرُ مَهْ غَفَرَ اللَّهُ لَكَ . فَقَالَ أَبُو بَكْرٍ إِنَّ هَذَا أَوْرَدَنِي الْمَوَارِدَ .
Malik related to me from Zayd ibn Aslam from his father that Umar ibn al-Khattab came upon Abu Bakr as-Siddiq pulling his tongue. Umar said to him, "Stop, may Allah forgive you!" Abu Bakr replied, "This has brought me to dangerous places."
Reference Muwatta Malik 518050
USC-MSA web (English) reference : Book 56, Hadith 12