Surah Al-Anbya 21:55

قَالُوٓا۟ أَجِئْتَنَا بِٱلْحَقِّ أَمْ أَنتَ مِنَ ٱللَّـٰعِبِينَ

They said, "Have you come to us with truth, or are you of those who jest?"

Translation: Saheeh International

Tafsir

They said ‘Do you bring us the truth in that which you are saying or are you being frivolous?’ in this regard.

Excerpt from Tafsir al-Jalalayn, commentary on 21:55, via Quran.com. The reader has the full commentary and 9 more tafsirs.