Surah At-Tariq 86:14
وَمَا هُوَ بِٱلْهَزْلِ
And it is not amusement.
Translation: Saheeh International
Tafsir
and it is not a jest frivolity or falsehood.
Excerpt from Tafsir al-Jalalayn, commentary on 86:14, via Quran.com. The reader has the full commentary and 9 more tafsirs.