Muwatta Malik #1949
Speech
The Arabic includes the chain of narration (sanad) and the collector's commentary; the English translation shows the Prophet's words only.
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."
About Muwatta Malik
This hadith is #1949 from Muwatta Malik, in the Book of Speech.