Sura al-Qaṣaṣ 28:49

قُلْ فَأْتُوا۟ بِكِتَٰبٍ مِّنْ عِندِ ٱللَّـهِ هُوَ أَهْدَىٰ مِنْهُمَآ أَتَّبِعْهُ إِن كُنتُمْ صَٰدِقِينَ

qul fa-ʾtū bi-kitābin min ʿindi allāhi huwa ahdā minhumā attabiʿhu in kuntum ṣādiqīna

Say: "Then bring ye a Book from Allah, which is a better guide than either of them, that I may follow it! (do), if ye are truthful!"