It was narrated that 'Abdullah bin Mas'ud said: "When we performed prayer with the Prophet P.B.U.H we said: 'Peace be upon Allah from His slaves, peace be upon Jibra'il and Mikail and so-and-so and so-and-so.' The Messenger of Allah P.B.U.H heard us and said: 'Do not say peace (Salam) be upon Allah, for He is As-Salam. When you sit (during prayer) say: At-Tahiyyatu lillahi was-salawatu wat-tayyibatu; assalamu 'alayka ayyuhan-Nabiyyu wa rahmatullahi wa barakatuhu; assalamu 'alayna wa 'ala 'ibadillahissalihin (All compliments, prayers and good words are due to Allah; peace be upon you, 0 Prophet, and the mercy of Allah and His blessings; peace be upon us and upon the righteous slaves of Allah)." For if you say that it will reach every righteous slave in the heavens and on earth. (Then say:) "Ashhadu an la ilaha ….iilallah wa ashhadu anna Muhammadan 'abduhu wa Rasuluhu (I bear witness that none has the right to be worshiped but Allah, and I bear witness that Muhammad P.B.U.H: His slave and Messenger). (Sahih) (Another chain) with similar wording. (Another chain) that 'Abdullah bin Mas'ud said: "The Prophet P.B.U.H used to teach us the Tashah-hud." And he mentioned similarly.