Surah Al-Fat'h (The Victory), Verse 18

لَقَدْ رَضِیَ اللّٰهُ عَنِ الْمُؤْمِنِیْنَ اِذْ یُبَایِعُوْنَكَ تَحْتَ الشَّجَرَةِ فَعَلِمَ مَا فِیْ قُلُوْبِهِمْ فَاَنْزَلَ السَّكِیْنَةَ عَلَیْهِمْ وَاَثَابَهُمْ فَتْحًا قَرِیْبًا ۟

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

“Allah's Good Pleasure was on the Believers when they swore Fealty to thee under the Tree: He knew what was in their hearts, and He sent down Tranquillity to them; and He rewarded them with a speedy Victory;”

Quran 48:18 (Yusuf Ali Translation)