The Divine Good Pleasure descended upon the believers when they swore eternal loyalty to you beneath the mystic tree. Allah Most High knew what was in their hearts, so He sent down profound tranquility upon them and rewarded them with true victory.
لَقَدْ رَضِيَ اللَّهُ عَنِ الْمُؤْمِنِينَ إِذْ يُبَايِعُونَكَ تَحْتَ الشَّجَرَةِ فَعَلِمَ مَا فِي قُلُوبِهِمْ فَأَنْزَلَ السَّكِينَةَ عَلَيْهِمْ وَأَثَابَهُمْ فَتْحًا قَرِيبًا
Laqad radiyal laahu 'anil mu'mineena iz yubaayi 'oonaka tahtash shajarati fa'alima maa fee quloobihim fa anzalas sakeenata 'alaihim wa asaa bahum fat han qareebaa