as He mentions in this verse. Falling down chin-first is itself an intended act of worship, just as placing the forehead on the ground is an intended act of worship. This is indicated by His words, Most High:

“Indeed, those who were given knowledge before it, when it is recited to them, fall down upon their chins in prostration,

and say, ‘Glory be to our Lord! Surely the promise of our Lord will be fulfilled.’

And they fall down upon their chins, weeping, and it increases them in humility.”

He thus commends and praises these people for falling down “upon their chins”—that is, onto their chins—in prostration; and, secondly, for falling down “upon their chins”—that is, onto them—while weeping. This makes clear that falling down chin-first is itself an intended act of worship that Allah loves. Falling down does not mean pressing the chin against the ground as the forehead is pressed against it. Rather, falling down chin-first marks the beginning of bowing, while prostration is the culmination of that descent. A person prostrates upon his forehead, not his chin, but he descends chin-first. The chin is the lower extremity of the face, its lowest part and the closest to the ground. Thus, when someone descends chin-first, his face and head descend in submission to Allah. From that moment, prostration has begun. Just as placing the forehead on the ground is the final stage of prostration, descending chin-first is its first stage. A full descent begins from standing or sitting.

It has been reported from Ibn ‘Abbās that “They fall down upon their chins” means “upon their faces.”

Al-Zajjāj said:

“A person who falls down from standing falls upon his face. The chin is where the two jawbones meet, and it is the cartilaginous part of the face. When he begins to fall, the part of his face closest to the ground is his chin.”