Surah As-Saffat 37:35

إِنَّهُمْ كَانُوٓا۟ إِذَا قِيلَ لَهُمْ لَآ إِلَـٰهَ إِلَّا ٱللَّهُ يَسْتَكْبِرُونَ

Indeed they, when it was said to them, "There is no deity but Allāh," were arrogant

Translation: Saheeh International

Tafsir

For truly it was they who in other words it was these sinners who — given the context that follows — when it was said to them ‘There is no god except God’ used to be scornful

Excerpt from Tafsir al-Jalalayn, commentary on 37:35, via Quran.com. The reader has the full commentary and 9 more tafsirs.