Quran 40:30 from Surah Ghafir on Divine Marvels.
وَقَالَ ٱلَّذِيٓ ءَامَنَ يَٰقَوۡمِ إِنِّيٓ أَخَافُ عَلَيۡكُم مِّثۡلَ يَوۡمِ ٱلۡأَحۡزَابِ
English translation: And said (he) who believed O my people! Indeed I [I] fear for you like (the) day (of) the companies
Transliteration: waqala alladhi amana yaqawmi inni akhafu alaykum mith'la yawmi al-ahzabi