Sahih Muslim 1842
Sahih Muslim · Book 33: The Book on Government · The obligation of fulfilling oaths of allegiance is owed to the first of two Caliphs
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، وَعَبْدُ اللَّهِ بْنُ بَرَّادٍ الأَشْعَرِيُّ ، قَالاَ حَدَّثَنَا عَبْدُ اللَّهِ، بْنُ إِدْرِيسَ عَنِ الْحَسَنِ بْنِ فُرَاتٍ ، عَنْ أَبِيهِ ، بِهَذَا الإِسْنَادِ مِثْلَهُ .
The same tradition has been transmitted by a different chain of narrators.