As the scripture plainly declares, Shearjashub was Isaiah's son. His name means, "the remnant shall return." We learn of another of his sons in Isa. 8:1. Both sons had unusual names with prophetic significance. With his other son, the Lord instructs him to name his son, Maher-shalal-hash-baz, signifying the imminent destruction of Israel.
"The conduit or tunnel that carried water from the city's only water source, called Gihon Spring, still exists and is located just outside of what used to be the city wall. This made the city very vulnerable in time of siege. The king might have come to this upper pool of Gihon Spring to consider the means by which the city could be defended. But with his heart filled with apostasy and his mind muddled with anxiety over the imminent attack of a huge army from the north, Ahaz would certainly not be in a mood to feel sympathetic to what Isaiah was about to tell him." (W. Cleon Skousen, Isaiah speaks to Modern Times, 201 as taken from Commentaries on Isaiah in the Book of Mormon, ed. by K. Douglas Bassett, [American Fork, UT: Covenant Publishing Co., 2003], 128)