What does Matthew 2:21 mean?

Joseph believed and obeyed God repeatedly. It could not have been easy to serve as the earthly father to the Son of God. The circumstances of Jesus' conception were controversial (Matthew 1:19–20). His birth was difficult and dramatic (Luke 2:1–7). The family even had to flee for their lives (Matthew 2:13–14)—all for a child who was not Joseph's own flesh and blood.

Scripture never gives any hint that Joseph hesitated to fulfill the role of protector and provider for Jesus. He immediately obeyed the commands to marry Mary, though she was pregnant. He dutifully packed up and left town immediately to live in foreign Egypt. Now, he returns from Egypt to Israel when commanded to do so by an angel in another dream.

Joseph is rarely given credit for the pivotal role he played in the life of Christ. Part of this, at least, is because he is not mentioned in the gospels after Jesus' youth. More than likely, he was older than Mary and had passed away before Jesus began His active ministry. Still, Joseph was clearly a man of faith and devotion to God's will. He followed the Lord's direction, despite what it cost in terms of his public reputation and lifestyle.