Ibn ‘Abbas said:The Messenger of Allah( may peace be upon him) used to teach us the tashahhud as he would teach us the Qur’an, and would say: The blessed adoration of the tongue, acts of worship (and) all good things are due to Allah. Peace be upon you, O Prophet, and Allah’s mercy and His 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 Allah’s apostle (peace be upon him)

English translation · Sunan Abu Dawud