John Gill Commentary Matthew 21:10

"And when he was come into Jerusalem, all the city was stirred, saying, Who is this?" — Matthew 21:10 (ASV)

And when he was come into Jerusalem .
&c.] The metropolis of the nation, the seat of the ancient kings of Judah, and of his father David, entering into it in this very public manner; as he never did before; riding in the manner the ancient judges and kings of Israel did, attended with a numerous retinue, shouting as they went along, and singing their "Hosannas" to him:

all the city was moved ;
as Bethlehem was, when Naomi with Ruth returned thither; and of which the same phrase is used, as here, (Ruth 1:19) .

all the city was moved about them ;
which the Chaldee paraphrase renders,

``all the inhabitants of the city were gathered in troops about them.'' And so here the sense is, that the inhabitants of the city of Jerusalem were in general alarmed at the uncommon apparatus, and shouting, and ran in great numbers to inquire what was the matter:

saying, who is this ?
They knew him not; for though he had preached to them, and wrought miracles among them, yet they had never seen him in any such pomp and state; and could not devise who he should be, that entered their city in such a manner, amidst the shouts and acclamations of so great a multitude: it seemed greatly to affect them, and fill them with concern, astonishment, and fear.