Sahih al-Bukhari 7272
Narrated `Abdullah bin Dinar:
`Abdullah Bin `Umar wrote to `Abdul Malik bin Marwan, swearing allegiance to him: 'I swear 
allegiance to you in that I will listen and obey what is in accordance with the Laws of Allah and the 
Tradition of His Apostle as much as I can.'
حَدَّثَنَا إِسْمَاعِيلُ، حَدَّثَنِي مَالِكٌ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَتَبَ إِلَى عَبْدِ الْمَلِكِ بْنِ مَرْوَانَ يُبَايِعُهُ، وَأُقِرُّ لَكَ بِالسَّمْعِ وَالطَّاعَةِ عَلَى سُنَّةِ اللَّهِ وَسُنَّةِ رَسُولِهِ، فِيمَا اسْتَطَعْتُ‏.‏