Quran 3:125 — The Amramites (Ali-'Imran)

Indeed, if you steadfastly persevere and maintain righteousness, then they attack you suddenly, your Lord will support you with five thousand* angels, well trained.

[3:124] You told the believers, "Is it not enough that your Lord supports you with three thousand angels, sent down?"

[3:126] GOD thus informs you, in order to give you good news, and to assure your hearts. Victory comes only from GOD, the Almighty, Most Wise.