—those who had been granted knowledge before the Qur’an—whenever it is recited to them, they fall down in prostration.

The plain sense here is an unrestricted act of prostration, like the prostration of Pharaoh’s sorcerers. It is also comparable to His words, “And enter the gate in a state of prostration and say, ‘Remove from us our burdens’” (al-Baqara 2:58), even though the posture intended there is bowing. Prostration, then, signifies humility and submissiveness; for this reason the term is commonly used to express humble deference.

As the poet said:
You see the knolls there bowed low beneath the hooves.

A group of lexicographers have stated, “Prostration means humility and submission,” and they cited: