Ibn Ezra

Therefore the Lord himself etc. Though you do not ask a sign, He will give it you. It is to me a matter of surprise that there are those who say the prophet here refers to Jesus, since the sign was given to Ahaz, and Jesus was born many years afterwards; besides, the prophet says, For before the child shall know to refuse the evil and choose the good, the land shall be forsaken; but the countries of Ephraim and Syria were wasted in the sixth year of Hezekiah, and it is distinctly said of whose two kings, etc. Many make the mistake of identifying Immanuel with Hezekiah; they cannot be the same, granting even this prophecy to have been uttered at the beginning of the reign of Ahaz; he reigned only sixteen years, and Hezekiah was at the death of Ahaz twenty-five years old. According to others, Immanuel is another son of Ahaz, and others again take the names (Immanuel, Maher Shalal and Shear Yashub) as symbolical of the kingdom; but if so, what meaning would be in the child’s knowing good and evil and in Maher Shalal calling father and mother? (8:4). I think that Immanuel is the son of Isaiah, as well as Maher Shalal; the latter is proved by And I went unto the prophetess, etc. (8:3). Shear Yashub is similarly related to the prophet (ver. 3); each of the three sons received a name that contained some hint at future events; Immanuel implied that God would help them and be with them during the troubles caused by the two kings; Maher Shalal, that the time for the exile of Samaria had arrived; and Shear Yashub, that the remnant of Israel would repent; this explanation is well borne out by the words, Behold, I and the children whom the Lord hath given me, are for signs and for wonders. Comp. The children which the Lord hath graciously given to thy servant (Gen. 33:5). Those that in the former passage regard children as equivalent to pupils must produce us some analogy from Scripture. Isaiah himself was a sign and an example concerning Egypt (20:3).—The Gaon says that the sign consisted in the child being a male child; but in my opinion the sign was that the child was to eat butter and honey; for it is not usual that children eat these things immediately after their birth. after its birth. We know that a male child is called נער, a female child נערה or עלמה—the feminine of עֶלֶם—whether she be a virgin or not; for עלמה signifies a person of a certain age, like the masculine עלם; and in דרך גבר בעלמה the way of a man with a young woman (Prov. 30:19) עלמה is certainly not a virgin; because at the beginning of that passage it is said, which I know not (ibid. 18). וקראת And shall call. Subject is, העלמה; comp. וחטאת And it sinneth (Ex. 5:16).