Matthew 1:23 “Behold, the virgin shall be with child and shall bear a Son, and they shall call His name Immanuel,” which translated means, “God with us.”
Introduction - two verses that introduce us to the truth of the incarnation
The first passage, Matthew 1:23, records the fact that the Person of the Son is no less than true Deity by way of the title "Immanuel". This title, originating from Isaiah 7:14, is translated by Matthew into the phrase: "God with us". The passage is situated in a conversation that the angel Gabriel is having with Joseph - Jesus' legal earthly father.
The concern is to communicate to Joseph the conditions of his espoused fiance's pregnancy. How is it that his fiance, Mary, could be pregnant? The angel utilizes the prophecy of Isaiah 7:14 to indicate that no wrong-doing had been done by her, since she remained a virgin. The miracle of the virgin birth/conception was to provide the way in which the Divine Person of the Son could enter from eternity into time. By not having a human father, the humanity of the Son would by-pass the sin nature that travels via the fathers bloodline (see for example 1 Peter 1:18-19). Henceforth, the baby developing in Mary's womb was, with respect to His identity, truly God who came to be also truly man.
John 1:14, the second verse cited at the beginning of this post, tells us that the Divine Person of the Son "became flesh". In what is the clearest declaration of what theologians call "the incarnation", the Eternal second Person of the Trinity came by means of the virgin conception described in Matthew 1:23 and "became" or "assumed unto His person" a second way of expressing His unparalleled life - namely a true and full humanity. In so far as Matthew 1:23 points to the reality of Jesus Christ as "God incarnate", John 1:14 serves to explain what the reality of the incarnation is - namely "The Word" or "The Son" becoming human flesh.
How the Baptist Faith and Message unpacks the doctrine of the incarnation of the Son of God
The Baptist Faith & Message 2000 is the official doctrinal statement of the Southern Baptist Convention. It's value lies in explaining and summarizing all the relevant scriptures that speak on various doctrinal subjects. With regard to the truth of Jesus' incarnation, the Baptist Faith and Message 2000 (henceforth BFM 2000) states the following:
"Christ is the eternal Son of God. In His incarnation as Jesus Christ He was conceived of the Holy Spirit and born of the virgin Mary. Jesus perfectly revealed and did the will of God, taking upon Himself human nature with its demands and necessities and identifying Himself completely with mankind yet without sin."