God’s covenant with His people is recorded early in history: the rainbow as a sign of His promise not to destroy the earth again, a promise to Abraham to increase his descendants to as many as the stars in the sky, or the sands of the sea, the renewal of the broken bond of fellowship with His idolatrous people, the faithful remnant, then finally that a descendant of David would rule His people, including all nations.
So Isaiah’s announcement that a virgin would bear a son whose name, Immanuel, means “God with us” must have not seemed very clear to God’s people. God had already promised to be with His people, many times in many ways, and had proven His faithfulness over and over again.
Yet generations later, when a teenager is told she is with child by the Holy Spirit, and her betrothed husband plans to quietly divorce himself from their planned marriage, he is assured by the Lord in a dream about the true nature of this pregnancy. Matthew reminds us of the Old Testament promise of a son to come, and suddenly it becomes clear: God will be living with us, as a man, born of woman. There is no greater covenant than God walking alongside us, knowing us as son, brother, friend, teacher and in the ultimate bond with His people, dying in our place. God with us, God in our place, God fulfilling His promises–always.
Isaiah 7:14 and Matthew 1:23