Al-An'aam • BN-TAFSEER-IBN-E-KASEER
﴿ وَأَقْسَمُوا۟ بِٱللَّهِ جَهْدَ أَيْمَٰنِهِمْ لَئِن جَآءَتْهُمْ ءَايَةٌۭ لَّيُؤْمِنُنَّ بِهَا ۚ قُلْ إِنَّمَا ٱلْءَايَٰتُ عِندَ ٱللَّهِ ۖ وَمَا يُشْعِرُكُمْ أَنَّهَآ إِذَا جَآءَتْ لَا يُؤْمِنُونَ ﴾
“Now they swear by God with their most solemn oaths that if a miracle were shown to them, they would indeed believe in this [divine writ]. Say: "Miracles are in the power of God alone." And for all you know, even if one should be shown to them, they would not believe”
Please check ayah 6:110 for complete tafsir.