حَدَّثَنَا يَحْيَى بْنُ أَيُّوبَ، وَقُتَيْبَةُ، وَابْنُ، حُجْرٍ - وَاللَّفْظُ لاِبْنِ أَيُّوبَ - قَالُوا حَدَّثَنَا إِسْمَاعِيلُ، - وَهُوَ ابْنُ جَعْفَرٍ - أَخْبَرَنِي عَبْدُ اللَّهِ بْنُ دِينَارٍ، أَنَّهُ سَمِعَ عَبْدَ اللَّهِ بْنَ عُمَرَ، يَقُولُ كُنَّا نُبَايِعُ رَسُولَ اللَّهِ صلى الله عليه وسلم عَلَى السَّمْعِ وَالطَّاعَةِ يَقُولُ لَنَا ‏"‏ فِيمَا اسْتَطَعْتَ ‏"‏ ‏.‏

It has been narrated on the authority of Abdullah b. 'Umar who said: We used to take oath to the Messenger of Allah (PBUH) that we would listen to and obey his orders. He would tell us (to say in the oath): As far as it lies in my power. Translation Not Available

Book Ref: Sahih Muslim Book 33 Hadith 4604
Web Ref:  Sahih Muslim Book 20 Hadith 1867