Verse 14 does not have to be plucked out and made into a prophecy for Jesus. It is clear from the context that it is a prophecy referring to Jesus.
(Verse 10) The lord spoke to Ahaz.
(Verse 11) Asking for
a sign of the Lord thy God.
(Verse 14)
The Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, (Jesus)
(Verses 15) Refers to Jesus, who would know to refuse the evil, and choose the good
Isaiah 7
King James Version
10 Moreover the Lord spake again unto Ahaz, saying,
11 Ask thee a sign of the Lord thy God; ask it either in the depth, or in the height above.
12 But Ahaz said, I will not ask, neither will I tempt the Lord.
13 And he said, Hear ye now, O house of David; Is it a small thing for you to weary men, but will ye weary my God also?
14 Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel.
15 Butter and honey shall he eat, that he may know to refuse the evil, and choose the good.