An angel of the Lord appeared to him in a dream, saying, "Joseph, son of David, do not fear to take Mary as your wife, for that which is conceived in her is from the Holy Spirit. She will bear a son, and you shall call his name Jesus, for he will save his people from their sins."
Our chief need was not for a teacher.
Our chief need was not for an example.
We were lost in sin, rebellious and prone to evil. So he sent a savior.
Yes, Jesus was a teacher, and he lived a life we should try to follow. But most of all he came to save, to "give his life as a ransom for many."
There are those who, as Spurgeon said, "cry up Jesus as Messiah, sent of God, to exhibit a grand example and supply a pure code of morals, but they cannot endure Jesus as a Saviour, redeeming us by his blood, and by his death delivering us from sin." They "speak only of him as a prophet, a teacher, or a leader, and care not for him as a Saviour ...." These people do not know him.
To know him is to take him as God has revealed him. "You shall call his name Jesus, for he will save his people from their sins" (Matt 1:21).
Let us rejoice that God saw our true need and met it.