She will bear a Son; and you shall call His name Jesus, for He will save His people from their sins. (Matthew 1:21)The word "saved" implies danger. There is no need to be saved if there is nothing to be saved from. The Jews in the first century wanted deliverance. They wanted to be saved from a secular government, but many did not realize that they first needed to be rescued from something else. They needed to be saved from their sins.
At His first coming, Jesus did not come to rule, but to die. He came to save His people from their sin. The supreme irony was that He came not only to save Jewish people, but also the Gentiles. The wicked heathen people whom the Jews had separated themselves from would be saved by the Messiah! Praise God for His great and wide grace!
Doubtless, Joesph might have confined the words spoken by the angel, "His people," to include only the Jews. But these words contain a much wider scope of people, these words include the redeemed people of all ages. They include both Jews and Gentiles. They include Enoch and Noah. They include Melchizedek, Abraham, Isaac, and Jacob. They include Moses, Ruth, David, Esther, and all the rest of the redeemed, both in the past and those yet to be born. All of these people are saved by God, saved from their sin, and granted that which they do not deserve.
Jesus came to save His people from their sins! He came to save His people from that which they rightly deserved! The final penalty for sin is eternal damnation. Hell. The wrath of God. But Christ bore His people's punishment on the cross; He bore the wrath of God in order to make salvation possible!
After the angel of the Lord had finished his explanation concerning the purpose of the Messiah, Joesph's dream was complete. When Joseph woke up, he obediently acted according to the words of the angel and took Mary as his wife.
Jesus' Purpose: To Save His People From Their Sins (Part 1) - Matthew 1:21
Joseph, Do Not Be Afraid to Take Mary as Your Wife - Matthew 1:20
Joseph's Dilemma - Matthew 1:19
The Virgin Birth - Matthew 1:18
Isaiah's Prophecy: It's Fulfillment (Part 1) - Matthew 1:22-23