Qur'ān 6:109 · Al-An'am (الأنعام)

وَأَقْسَمُوا۟ بِٱللَّهِ جَهْدَ أَيْمَـٰنِهِمْ لَئِن جَآءَتْهُمْ ءَايَةٌۭ لَّيُؤْمِنُنَّ بِهَا ۚ قُلْ إِنَّمَا ٱلْـَٔايَـٰتُ عِندَ ٱللَّهِ ۖ وَمَا يُشْعِرُكُمْ أَنَّهَآ إِذَا جَآءَتْ لَا يُؤْمِنُونَ

And they swear by Allah their strongest oaths that if a sign came to them, they would surely believe in it. Say, "The signs are only with Allah." And what will make you perceive that even if a sign came, they would not believe.