ENOfficial
Jabir said that God’s Messenger used to say in his prayer after the tashahhud, “The best speech is God’s speech, and the best guidance is Muhammad’s guidance.” Nasa’i transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ جَابِرٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ فِي صَلَاتِهِ بَعْدَ التَّشَهُّدِ: «أَحْسَنُ الْكَلَامِ كَلَامُ اللَّهِ وَأَحْسَنُ الْهَدْيِ هدي مُحَمَّد» . رَوَاهُ النَّسَائِيّ
sunnah.com