وَأَقۡسَمُواْ بِٱللَّهِ جَهۡدَ أَيۡمَٰنِهِمۡ لَئِن جَآءَتۡهُمۡ ءَايَةٞ لَّيُؤۡمِنُنَّ بِهَاۚ قُلۡ إِنَّمَا ٱلۡأٓيَٰتُ عِندَ ٱللَّهِۖ وَمَا يُشۡعِرُكُمۡ أَنَّهَآ إِذَا جَآءَتۡ لَا يُؤۡمِنُونَ ١٠٩
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 (English)
Each word's meaning and sound
The idolaters swear by Allah, with their strongest oaths, that if Muhammad (peace be upon him) brings them one of the signs they asked for, then they will believe. Say to them, O Messenger: I do not have signs so that I may bring them: they are only with Allah, Who sends them down as He wills. And what will inform you, O believers, that if these signs come, as they request, they still will not believe? Instead, they will persist in their denial and stubbornness, because they in fact do not want to be guided.
Al-Mukhtasar in interpreting the Noble Quran