“And she shall bring forth a son, and thou shalt call his name Jesus: for he shall save his people from their sins.” Matthew 1:21
Christ became a man in order to fulfill all the OT law. Romans 8:3-4, “For what the law could not do, in that it was weak through the flesh, God sending his own Son in the likeness of sinful flesh, and for sin, condemned sin in the flesh: That the righteousness of the law might be fulfilled in us, who walk not after the flesh, but after the Spirit.”
Christ became a man so that he could be our compassionate High Priest – Hebrews 2:17, “Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.”
Christ became a man so he could be our substitute — die in our place on Calvary – 2 Cor. 5:21, “For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.” Hebrews 2:14, “Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;”
Christ became a man so that a race of men could rise from the dead – 1 Cor. 15:23, “But every man in his own order: Christ the firstfruits; afterward they that are Christ’s at his coming.”
Church History: Irenaeus, Clement of Alexandria and Tertullian, 2nd century church fathers according to J. Gresham Machen concludes that these men considered the virgin birth “as one of the essential facts about Christ which had a firm place in even the briefest summaries of the Christian faith.”
Ignatius,110: Argued the virgin birth of Christ against one type of Gnosticism known as Docetism as designation derived from the Greek word meaning “to seem.” This heresy taught that Christ only seemed to be corporeal.
Apostle’s Creed, 2nd century: “born of the virgin Mary.” Confessing that Jesus Christ was virgin born was part, with other essential doctrines, of the minimum of the Christian faith.
Apostle Luke: Luke has no doubt regarding the veracity of the account. See Luke 1:1-4, the certainty.