حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا أَبُو عَاصِمٍ، حَدَّثَنَا عِمْرَانُ، عَنْ قَتَادَةَ، عَنْ عَبْدِ رَبِّهِ، عَنْ أَبِي عِيَاضٍ، عَنِ ابْنِ مَسْعُودٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا تَشَهَّدَ ذَكَرَ نَحْوَهُ وَقَالَ بَعْدَ قَوْلِهِ ‏"‏ وَرَسُولُهُ ‏"‏ ‏.‏ ‏"‏ أَرْسَلَهُ بِالْحَقِّ بَشِيرًا وَنَذِيرًا بَيْنَ يَدَىِ السَّاعَةِ مَنْ يُطِعِ اللَّهَ وَرَسُولَهُ فَقَدْ رَشَدَ وَمَنْ يَعْصِهِمَا فَإِنَّهُ لاَ يَضُرُّ إِلاَّ نَفْسَهُ وَلاَ يَضُرُّ اللَّهَ شَيْئًا ‏"

Narrated Abdullah ibn Mas'ud

When the Messenger of Allah (ﷺ) recited the tashahhud, he would mention something similar and said after his statement 'And His Messenger': 'He sent him with the truth, as a bearer of glad tidings and a warner before the Hour. Whoever obeys Allah and His Messenger has been rightly guided, and whoever disobeys them both does not harm anyone except himself and does not harm Allah at all.'