The Quran

وَلَمّا رَأَى المُؤمِنونَ الأَحزابَ قالوا هٰذا ما وَعَدَنَا اللَّهُ وَرَسولُهُ وَصَدَقَ اللَّهُ وَرَسولُهُ ۚ وَما زادَهُم إِلّا إيمانًا وَتَسليمًا

Muhammad Asad

And [so,] when the believers saw the Confederates [advancing against them], they said, "This is what God and His Apostle have promised us!" - and, "Truly spoke God and His Apostle!"¹ - and all this but increased their faith and their readiness to surrender themselves unto God.

These seem to be allusions to 29:2 (which may have been one of the last Meccan revelations) as well as to 2:155 and 214 (i.e., verses of the first surah of the Medina period).