A general Muslim term for those who pledged allegiance under the tree
لَقَدْ رَضِيَ اللَّهُ عَنِ الْمُؤْمِنِينَ إِذْ يُبَايِعُونَكَ تَحْتَ الشَّجَرَةِ فَعَلِمَ مَا فِي قُلُوبِهِمْ فَأَنْزَلَ السَّكِينَةَ عَلَيْهِمْ وَأَثَابَهُمْ فَتْحًا قَرِيبًا {18}
Allah was Pleased from the Momineen when they pledged their allegiances to you under the tree, and He Knew what was in their hearts, so He Sent down the tranquillity upon them and Rewarded them with a near victory [48:18]
محمد بن العباس، قال: حدثنا محمد بن أحمد الواسطي، عن زكريا بن يحيى، عن إسماعيل بن عثمان، عن عمار الدهني، عن أبي الزبير، عن جابر عن أبي جعفر (عليه السلام)، قال: قلت: قول الله عز و جل: لَقَدْ رَضِيَ اللَّهُ عَنِ الْمُؤْمِنِينَ إِذْ يُبايِعُونَكَ تَحْتَ الشَّجَرَةِ كم كانوا؟ قال: «ألفا و مائتين» قلت: هل كان فيهم علي (عليه السلام)؟ قال: «نعم [علي] سيدهم و شريفهم
Muhammad Bin Al-Abbas, from Muhammad Bin Ahmad Al-Wasity, from Zakariyya Bin Yahya, from Ismail Bin Usman, from Amaar Al-Dahny, from Abu Al-Zubeyr, from Jabir,
‘I asked from Abu Ja’far-asws, ‘(What about) the Words of Allah-azwj Mighty and Majestic: Allah was Pleased from the Momineen when they pledged their allegiances to you under the tree [48:18], how many were they?’ He-asws said: ‘One thousand two hundred’. I said, ‘Was Ali-asws among them?’ He-asws said: ‘Yes, Ali-asws was the Chief of them, and the most noble of them’.[1]
[1] تأويل الآيات 2: 595/ 7.