It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) taught him the words of Tashahhud and ordered him to teach them to the people as well: «التَّحِيَّاتُلِلّٰهِوَالصَّلَوَاتُوَالطَّيِّبَاتُالسَّلَامُعَلَيْكَأَيُّهَاالنَّبِيُّوَرَحْمَةُاللّٰهِوَبَرَكَاتُهُالسَّلَامُعَلَيْنَاوَعَلَىعِبَادِاللّٰهِالصَّالِحِينَأَشْهَدُأَنْلَاإِلٰهَإِلَّااللّٰهُوَأَشْهَدُأَنَّمُحَمَّدًاعَبْدُهُوَرَسُولُهُ» The translation of which is: “All verbal, physical, and bodily acts of worship are for Allah alone. O Prophet (peace and blessings be upon you)! Peace be upon you, and may Allah’s mercy and blessings descend upon you. Peace be upon us and upon the righteous servants of Allah. I bear witness that there is no deity except Allah, and that Muhammad (peace and blessings be upon him) is Allah’s servant and His Messenger.”
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 3562
Hadith Gradingحکم دارالسلام:صحيح، خ: 831، م: 402، وهذا إسناد ضعيف الانقطاعه، أبو عبيدة لم يسمع من أبيه