Sayyiduna Ibn Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) used to teach us the tashahhud: "All greetings, all good words and all prayers are for Allah. Peace be upon you, O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous servants of Allah. I bear witness that there is no god but Allah, and I bear witness that Muhammad (peace and blessings be upon him) is His servant and His Messenger."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11358