It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) took his hand and taught him the words of Tashahhud: «التَّحِيَّاتُلِلّٰهِوَالصَّلَوَاتُوَالطَّيِّبَاتُالسَّلَامُعَلَيْكَأَيُّهَاالنَّبِيُّوَرَحْمَةُاللّٰهِوَبَرَكَاتُهُالسَّلَامُعَلَيْنَاوَعَلَىعِبَادِاللّٰهِالصَّالِحِينَأَشْهَدُأَنْلَاإِلٰهَإِلَّااللّٰهُوَأَشْهَدُأَنَّمُحَمَّدًاعَبْدُهُوَرَسُولُهُ» "All verbal, physical, and bodily acts of worship are for Allah alone. O Prophet (peace and blessings of Allah be upon you)! Peace be upon you, and the mercy and blessings of Allah 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 of Allah be upon him) is the servant of Allah and His Messenger." When you have done this, your prayer is complete; now if you wish to stand, then stand, and if you wish to remain seated, then remain seated."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 4006
Hadith Gradingحکم دارالسلام:إسناده صحيح، وذكر ابن حبان أن قوله فى آخر الحديث: فإذا قضيت هذا ..... إنما هو قول ابن مسعود، ليس من كلام النبى ، أدرجه زهير فى الخبر ، وكذلك قال الدارقطني فى السنن: 1/ 353، والعلل: 5/ 127.