Sunan an-Nasa’i 1277
The Book of Forgetfulness (In Prayer)
The obligation of tashahhud
It was narrated that Ibn Mas'ud said: "Before the tashahhud was enjoined, when we prayed we used to say: 'Peace (As-Salam) be upon Allah (SWT), pace be upon Jibril, peace be upon Mika'il.' The Messenger of Allah (ﷺ) said: 'Do not say this, for indeed Allah (SWT), the Mighty and Sublime, is As-Salam. Rather say: "At-tahiyyatu lillahi wasalawatu wat-tayibaat, as-salamu 'alaika ayah-Nabiyyu wa rahmatAllahi wa baraktuhu. As-salamu 'alaina a 'ala ibad illahis-salihin, ashadu an la ilaha ill Allah, wa ashhadu anna Muhammadan 'abduhu wa rasuluhu. (All compliments, prayers and pure words are due to Allah. Peace be upon you O Prophet, and the mercy of Allah and His blessings. Peace be upon us and upon the righteous slaves of Allah. I bear witness that that none has the right to be worshipped except Allah, and I bear witness that Muhammad is His slave and messenger.)"