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nasai-kubra:1235 – ʿAmr b. ʿAlī > Yaḥyá > Jaʿfar > Ibn Muḥammad from his father > Jābir

The Messenger of Allah ﷺ used to say in his prayer, after the tashahhud: "The best of word is the word of Allah (SWT) and the best of guidance is the guidance of Muhammad ﷺ." (Using translation from Nasāʾī 1311)  

الكبرى للنسائي:١٢٣٥ – أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ حَدَّثَنَا يَحْيَى عَنْ جَعْفَرٍ هُوَ ابْنُ مُحَمَّدٍ عَنْ أَبِيهِ عَنْ جَابِرٍ

أَنَّ رَسُولَ اللهِ ﷺ كَانَ يَقُولُ فِي صَلَاتِهِ بَعْدَ التَّشَهُّدِ «أَحْسَنُ الْكَلَامِ كَلَامُ اللهِ وَأَحْسَنُ الْهَدْيِ هَدْيُ مُحَمَّدٍ» ﷺ  

See similar narrations below:

Collected by Nasāʾī
nasai:1311 – ʿAmr b. ʿAlī > Yaḥyá > Jaʿfar b. Muḥammad from his father > Jābir

The Messenger of Allah ﷺ used to say in his prayer, after the tashahhud: "The best of word is the word of Allah (SWT) and the best of guidance is the guidance of Muhammad ﷺ."  

النسائي:١٣١١ – أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ قَالَ حَدَّثَنَا يَحْيَى عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ عَنْ أَبِيهِ عَنْ جَابِرٍ

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يَقُولُ فِي صَلاَتِهِ بَعْدَ التَّشَهُّدِ أَحْسَنُ الْكَلاَمِ كَلاَمُ اللَّهِ وَأَحْسَنُ الْهَدْىِ هَدْىُ مُحَمَّدٍ ﷺ