"The Messenger of Allah ﷺ used to teach us the tashahhud just as he used to teach us a surah from the Quran." (Using translation from Nasāʾī 1278)

عَنْ رَجُلٍ مِنْ أَصْحَابِ النَّبِيِّ ﷺ قَالَ كَانَ رَسُولُ اللهِ ﷺ يُعَلِّمُنَا التَّشَهُّدَ كَمَا يُعَلِّمُنَا السُّورَةَ مِنَ الْقُرْآنِ