Surah Al-Muddaththir 74:54

كَلَّآ إِنَّهُۥ تَذْكِرَةٌ

No! Indeed, it [i.e., the Qur’ān] is a reminder.

Translation: Saheeh International

Tafsir

No indeed! kallā a commencement of a new sentence Assuredly it that is the Qur’ān is a Reminder an admonition.

Excerpt from Tafsir al-Jalalayn, commentary on 74:54, via Quran.com. The reader has the full commentary and 9 more tafsirs.