John Gill Commentary Isaiah 7:3

"Then said Jehovah unto Isaiah, Go forth now to meet Ahaz, thou, and Shear-jashub thy son, at the end of the conduit of the upper pool, in the highway of the fuller`s field;" — Isaiah 7:3 (ASV)

Then said the Lord to Isaiah The prophet, the inspired penman of these prophecies, that go by his name; what follows, the Lord said to him in vision, or by an articulate voice, or by an impulse on his mind:

go forth now to meet Ahaz The prophet was in the city of Jerusalem, and Ahaz was without, as appears by the place after mentioned, where he was to meet him; perhaps Ahaz was at his country house, which, upon the news brought him of the designs of his enemies, he leaves, and betakes himself to Jerusalem, his metropolis, and fortified city, where he might be more safe; or he had been out to reconnoitre the passes about Jerusalem, and give orders and directions for the strengthening and keeping of them:

you, and Shearjashub your son whose name signifies "the remnant shall return", and who was taken with the prophet, to suggest either that the remnant that were left of the former devastations by those two kings ought to return to the Lord by repentance; or that though the people of Judah should hereafter be carried captive by the Assyrians, yet a remnant should return again. The Targum interprets this not of Isaiah's natural son, but of his disciples; paraphrasing it thus, ``you, and the rest of your disciples, who have not sinned, and are turned from sin:''

at the end of the conduit of the upper pool for there was an upper pool and a lower one; see (Isaiah 22:9):

in the highway of the fuller's field where they washed and dried their garments, and whitened them; the pool, conduit, and field, being fit for their purpose.