Surah Al-Mursalat 77:50

فَبِأَىِّ حَدِيثٍۭ بَعْدَهُۥ يُؤْمِنُونَ

Then in what statement after it [i.e., the Qur’ān] will they believe?

Translation: Saheeh International

Tafsir

In what discourse then after this namely the Qur’ān will they believe? In other words they cannot believe in any other of God’s Scriptures after having denied this Qur’ān since it comprises that inimitability i‘jāz which none of the others do.

Excerpt from Tafsir al-Jalalayn, commentary on 77:50, via Quran.com. The reader has the full commentary and 9 more tafsirs.