صَحِيحُ مُسْلِمٍ
Sahih Muslim 1859 c
The Book on Government
It is recommended for the army to swear allegiance to the ruler when intending to fight, and an account of Bay'at Ar-Ridwan beneath the tree
وَحَدَّثَنِي حَجَّاجُ بْنُ الشَّاعِرِ، وَمُحَمَّدُ بْنُ رَافِعٍ، قَالاَ حَدَّثَنَا شَبَابَةُ، حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ أَبِيهِ، قَالَ لَقَدْ رَأَيْتُ الشَّجَرَةَ ثُمَّ أَتَيْتُهَا بَعْدُ فَلَمْ أَعْرِفْهَا.
The tradition has been narrated on the authority of Sa'id b. Musayyib who learnt it from his father. The latter said: I had seen the tree. When I came to the spot afterwards, I could not recognise it.
Sahih Muslim, 1859 cSahihصحيح