إِن نَّشَأۡ نُنَزِّلۡ عَلَيۡهِم مِّنَ ٱلسَّمَآءِ ءَايَةً فَظَلَّتۡ أَعۡنَٰقُهُمۡ لَهَا خَٰضِعِينَ
If We willed, We could send down to them from the sky a sign for which their necks would remain humbled.
The Quraysh kept demanding tangible miracles; they wanted angels to be sent down from the sky, or to be shown something extraordinary that would compel them to believe.
Allah responds to this: if He truly wanted to force them to believe through a shattering, supernatural sign, He could easily do so. Their necks would bow down in forced humility, and they would have no choice but to submit.
Here is the profound mercy hidden in this statement: Allah chooses not to do this.
Why? Because earlier peoples were shown exactly such overwhelming signs, yet when they still disbelieved, they were destroyed at once.
That no such sign was sent to the Quraysh is in fact a manifestation of His mercy. For in this way they were given more time and opportunity to come to faith of their own free will, instead of being compelled and then suddenly destroyed.
The image of bowed necks is especially striking, because it evokes physical humiliation and a forced submission that never reaches the heart.
This is not the kind of faith Allah expects from His creation.