Behold, a virgin shall be with child - Matthew clearly understands this as applying literally to a virgin. Compare Luke 1:34. It thus implies that the conception of Christ was miraculous, or that the body of the Messiah was created directly by the power of God, agreeably to the declaration in Hebrews 10:5; “Wherefore, when he cometh into the world, he saith, Sacrifice and offering thou wouldest not, but a body hast thou prepared me.”
And they shall call his name Emmanuel - That is, his name shall be so called. See the notes at Isaiah 7:14. The word “Immanuel” is a Hebrew word, צמנוּאל ‛immânû'êl; cf. Ἐμμανουήλ Emmanouēl, and literally means “God with us.” Matthew doubtless understands it as denoting that the Messiah was really “God with us,” or that the divine nature was united with the human. He does not affirm that this was its meaning when used in reference to the child to whom it was first applied, but this is its signification as applicable to the Messiah. It was suitably expressive of his character; and in this sense it was fulfilled. When first used by Isaiah, it denoted simply that the birth of the child was a sign that God was with the Jews to deliver them. The Hebrews often incorporated the name of Yahweh, or God, into their proper names. Thus, Isaiah means “the salvation of Yah;” Eleazer, “help of God:” Eli, “my God,” etc. But Matthew evidently intends more than was denoted by the simple use of such names. He had just given an account of the miraculous conception of Jesus: of his being begotten by the Holy Spirit. God was therefore his Father. He was divine as well as human. His appropriate name, therefore, was “God with us.” And though the mere use of such a name would not prove that he had a divine nature, yet as Matthew uses it, and meant evidently to apply it, it does prove that Jesus was more than a man; that he was God as well as man. And it is this which gives glory to the plan of redemption. It is this which is the wonder of angels. It is this which makes the plan so vast, so grand, so full of instruction and comfort to Christians. See Philippians 2:6-8. It is this which sheds such peace and joy into the sinner’s heart; which gives him such security of salvation, and which renders the condescension of God in the work of redemption so great and his character so lovely.
“Till God in human flesh I see,
My thoughts no comfort find,
The holy, just, and sacred Three
Are terror to my mind.
But if immanuel’s face appears,
My hope, my joy, begins.
His grace removes my slavish fears.
His blood removes my sins.”
For a full examination of the passage, see Barnes’ notes at Isaiah 7:14.