Isaiah 7:3

The prophet is instructed to meet Ahaz at a certain point outside the city, taking his son with him for a sign to the king.

Shear-jashub "Remnant-shall-turn," i.e. "turn to Jehovah," not "return from exile" (ch. Isaiah 10:22). How much the name meant to Ahaz we cannot tell; nor is it clear whether the boy was present to have the incident impressed on his own memory, or to recall to the king's mind some earlier prophecy of Isaiah in which the name was explained. The latter seems more probable. In any case the name embodies a fundamental idea of Isaiah's ministry (see on ch. Isaiah 6:13), and if it conveyed any significance to Ahaz at this time it was a prediction at once of judgment and hope: a remnant shall turn; but onlya remnant!

at the end of the conduit … field On the same spot the Rabshakeh stood 34 years later and delivered Sennacherib's insulting message to Hezekiah. It seems therefore to have been within earshot of the wall (ch. Isaiah 36:2, cf. Isa 7:11; 2 Kings 18:17; 2 Kings 18:26). On what side of the city it is to be sought is as yet a matter of conjecture. (1) The "upper pool" is by many identified with the Birket el-Mamilla(about half a mile to the west of the city), from which a canal leads to reservoirs within the walls. In this case it would be difficult to explain the expression "go out to the end of the conduit," and besides the distance from the wall is too great. (2) Tradition fixes the site of the Assyrian camp on the north of the city, and here an ancient aqueduct (older than Herod's temple) has been discovered which pierces the wall to the east of the Damascus gate, and discharges into a large reservoir in the northern quarter of the city. If this reservoir be the "upper pool" the end of its conduit would be the northern extremity of the canal mentioned. (3) A third suggestion is that the "upper pool" like the "lower pool" (ch. Isaiah 22:9) was in the south of the city and inside the wall. It has been identified with a recently-discovered pool near the present pool of Siloam, and a conduit has also been excavated which carried its surplus water outside the wall, to where the "fuller's field" is thought to have been. Ahaz was at this anxious moment devoting his personal attention to the water supply of his capital. Operations were apparently in progress either for filling the reservoirs and cisterns within the city, or for stopping the sources that would be accessible to the enemy. In the historic sieges of Jerusalem the assailants always suffered more from scarcity of water than the defenders; and it is not impossible that the precautions taken on this occasion were the reason why the allies "were not able to fight against it."