Ibn `Abbas reported:The Messenger of Allah (ﷺ) used to teach us tashahhud just as he used to teach us a Surah of the Qur'an, and he would say: All services rendered by words, acts of worship, and all good things are due to Allah. Peace be upon you, O Prophet, and Allah's mercy and blessings. Peace be upon us and upon Allah's upright servants. I testify that there is no god but Allah, and I testify that Muhammad is the Messenger of Allah. In the narration of Ibn Rumh (the words are): "As he would teach us the Qur'an

Tawus narrated it on the authority of Ibn 'Abbas that he said:The Messenger of Allah (ﷺ) used to teach us tashahhud as he would teach us a Sura of the Qur'an