عَنْ أَبِي عُبَيْدَةَ بْنِ عَبْدِ اللَّهِ عَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ رَضِيَ اللَّهُ عَنْهُ قَالَ: عَلَّمَهُ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ التَّشَهُّدَ وَأَمَرَهُ أَنْ يُعَلِّمَ النَّاسَ: ((التَّحِيَّاتُ لِلَّهِ وَالصَّلَوَاتُ وَالطَّيِّبَاتُ، السَّلَامُ عَلَيْكَ أَيُّهَا النَّبِيُّ وَرَحْمَةُ اللَّهِ وَبَرَكَاتُهُ، السَّلَامُ عَلَيْنَا وَعَلَى عِبَادِ اللَّهِ الصَّالِحِينَ، أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا اللَّهُ، وَأَشْهَدُ أَنَّ مُحَمَّدًا عَبْدُهُ وَرَسُولُهُ))
It is narrated from Sayyiduna Abdullah bin Mas’ud (may Allah be pleased with him), who says that the Messenger of Allah (peace and blessings be upon him) taught him the Tashahhud and also instructed him to teach it to the people:
((All greetings, prayers, and pure words 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 is His servant and Messenger.))