هُوَ الَّذِي أَرْسَلَ رَسُولَهُ بِالْهُدَىٰ وَدِينِ الْحَقِّ لِيُظْهِرَهُ عَلَى الدِّينِ كُلِّهِ ۚ وَكَفَىٰ بِاللَّهِ شَهِيدًا
“He is the One Who has sent His Messenger with [right] guidance and the religion of Truth, making it prevail over all others. And sufficient is Allah as a Witness.”
This ayah is part of Surah al-Fath, revealed -- as this event's own significance note states -- "concerning this incident" (Q48:1), the Treaty of Hudaybiyyah.