Surah As-Saffat 37:29

قَالُوا۟ بَل لَّمْ تَكُونُوا۟ مُؤْمِنِينَ

They [i.e., the oppressors] will say, "Rather, you [yourselves] were not believers,

Translation: Saheeh International

Tafsir

They the ones who were followed say to them the followers ‘On the contrary! You were simply not believers for it would only be true that we led you astray if you had actually been believers in the first place and then rejected faith and followed us.

Excerpt from Tafsir al-Jalalayn, commentary on 37:29, via Quran.com. The reader has the full commentary and 9 more tafsirs.