In the first chapter of Matthew, Joseph the carpenter is visited by an angel who gives him an important message. Joseph had been thinking about what he should do because Mary was pregnant–and he knew the child was not his.
But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost. 21 And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins. 22 Now all this was done, that it might be fulfilled which was spoken of the Lord by the prophet, saying, 23 Behold, a virgin shall be with child, and shall bring forth a son, and they shall call his name Emmanuel, which being interpreted is, God with us. (Matthew 1:20-23)
There are three critical points regarding the divine nature of Jesus in these verses. First, Mary conceived a child “of the Holy Ghost”. This pregnancy was unusual to say the least. There was no human father who impregnated her. Rather, Jesus was conceived through the power of the Holy Spirit. The fact that Mary was a virgin is well established in Scripture, both in Matthew 1:23 and in the prophecy Matthew quotes.
Therefore the Lord himself shall give you a sign; Behold, a virgin shall conceive, and bear a son, and shall call his name Immanuel. (Isaiah 7:14)
In addition, Mary herself admits this fact.
And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS. Then said Mary unto the angel, How shall this be, seeing I know not a man? (Luke 1:31, 34)
So the Holy Spirit, Who is also divine, brought about Mary’s miraculous conception of Jesus. So the sin nature of mankind was not passed down to Jesus. (Romans 5:12; Hebrews 4:15) This is vital to the doctrine of Jesus’ divinity.
Second, the child’s name is “Jesus: for he shall save his people from their sins.” (Matthew 1:21) Only God can forgive sin. (Jeremiah 31:34; Mark 2:7; Luke 5:21; Romans 3:25) And that is exactly what Jesus did. He removed our sin from us and nailed it to His cross. (Colossians 2:14) Jesus’ name means “Jehovah is salvation”. That’s Who He is. He is Jehovah. He is salvation. He is the One Who saves us from our sins.
Third, Jesus is called “Emmanuel”. As Matthew 1:23 states, this name means “God with us”. Jesus was the personification of God Himself. This is consistent with John 14:9 where Jesus tells Philip, “he that hath seen me hath seen the Father.” The angel revealed to Joseph that the child in Mary is God in the flesh.