Qasim bin Mukhaimara narrated that Alqama held my hand and narrated a hadith to me that Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) held his hand and said that the Messenger of Allah (peace and blessings be upon him) held Abdullah's hand and taught him how to recite the Tashahhud in prayer, and «(اَلتَّحِيَّاتُلِلّٰهِوَالصَّلَوَاتُوَالطَّيِّبَاتُ ........... إِلَىالصَّالِحِيْن)» Zuhair said: I think he made him memorize it up to « أَشْهَدُأَنْلَاإِلٰهَإِلَّااللّٰهُوَأَشْهَدُأَنَّمُحَمَّدًاعَبْدُهُوَرَسُوْلُهُ », he became doubtful in the two testimonies. Then he said: When you have done or said so, then complete your prayer, and if you wish to stand up, then stand up, and if you wish to remain seated, then remain seated.
Hadith Referenceسنن دارمي / من كتاب الصللاة / 1378