The Statement of Allah the Most High: "...When they gave their Bai'a (pledge) to you (O Muḥammad pbuh) under the tree..." (V.48:18)
حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا شَبَابَةُ، حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، قَالَ سَمِعْتُ عُقْبَةَ بْنَ صُهْبَانَ، عَنْ عَبْدِ اللَّهِ بْنِ مُغَفَّلٍ الْمُزَنِيِّ، إِنِّي مِمَّنْ شَهِدَ الشَّجَرَةَ، نَهَى النَّبِيُّ صلى الله عليه وسلم عَنِ الْخَذْفِ.
Narrated `Uqba bin Sahban: `Abdullah bin Mughaffal Al-Muzani who was one of those who witnessed (the event of) the tree, said, "The Prophet (ﷺ) forbade the throwing of small stones (with two fingers)."