Surah Al-An'am 6:109

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

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

Translation: Saheeh International

Tafsir

They that is the disbelievers of Mecca have sworn by God the most earnest oaths that if there came to them a sign of what they requested they will believe in it. Say to them ‘Signs are only with God’ and He sends them down as and when He wills; I am but a warner. …

Excerpt from Tafsir al-Jalalayn, commentary on 6:109, via Quran.com. The reader has the full commentary and 9 more tafsirs.