Surah Al-Qasas 28:49

قُلْ فَأْتُوا۟ بِكِتَـٰبٍ مِّنْ عِندِ ٱللَّهِ هُوَ أَهْدَىٰ مِنْهُمَآ أَتَّبِعْهُ إِن كُنتُمْ صَـٰدِقِينَ

Say, "Then bring a scripture from Allāh which is more guiding than either of them that I may follow it, if you should be truthful."

Translation: Saheeh International

Tafsir

Say to them ‘Then bring some Scripture from God that is better in guidance than these two Scriptures that I may follow it if you are truthful’ in what you say.

Excerpt from Tafsir al-Jalalayn, commentary on 28:49, via Quran.com. The reader has the full commentary and 9 more tafsirs.