Surah Ghafir 40:30

وَقَالَ ٱلَّذِىٓ ءَامَنَ يَـٰقَوْمِ إِنِّىٓ أَخَافُ عَلَيْكُم مِّثْلَ يَوْمِ ٱلْأَحْزَابِ

And he who believed said, "O my people, indeed I fear for you [a fate] like the day of the companies -

Translation: Saheeh International

Tafsir

Then said he who believed ‘O my people! Truly I fear for you a day like the day of the factions in other words the day of one faction being destroyed after another;

Excerpt from Tafsir al-Jalalayn, commentary on 40:30, via Quran.com. The reader has the full commentary and 9 more tafsirs.