Narrated 'Abdullah bin Dinar:

I witnessed Ibn 'Umar when the people gathered around 'Abdul Malik. Ibn 'Umar wrote: I gave the Pledge of allegiance that I will listen to and obey Allah's Slave, 'Abdul Malik, Chief of the believers according to Allah's Laws and the Traditions of His Apostle as much as I can;
and my sons too, give the same pledge.'

حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا يَحْيَى، عَنْ سُفْيَانَ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دِينَارٍ، قَالَ شَهِدْتُ ابْنَ عُمَرَ حَيْثُ اجْتَمَعَ النَّاسُ عَلَى عَبْدِ الْمَلِكِ ـ قَالَ ـ كَتَبَ إِنِّي أُقِرُّ بِالسَّمْعِ وَالطَّاعَةِ لِعَبْدِ الْمَلِكِ أَمِيرِ الْمُؤْمِنِينَ عَلَى سُنَّةِ اللَّهِ وَسُنَّةِ رَسُولِهِ مَا اسْتَطَعْتُ، وَإِنَّ بَنِيَّ قَدْ أَقَرُّوا بِمِثْلِ ذَلِكَ.