A review of Luke chapter one may help.
Upon learning that his wife would bear a child who would pave the way for the Messiah, Zacharias was filled with the Holy Spirit and spoke these words about Jesus, inspired by the Holy Spirit.
The following is an excerpt of his speech taken from Luke 1:68-75
Blessed be the Lord God of Israel,
For He has visited us and accomplished redemption for His people,
And has raised up a horn of salvation for us
In the house of David His servant—
As He spoke by the mouth of His holy prophets from of old—
Salvation from our enemies,
And from the hand of all who hate us;
To show mercy toward our fathers,
And to remember His holy covenant,
The oath which He swore to Abraham our father,
To grant us that we, being rescued from the hand of our enemies,
Might serve Him without fear,
In holiness and righteousness before Him all our days.
During the Millennial Period, God will fulfill his promise to Israel. They will be led by a king from the line of David, find redemption, and experience salvation from their enemies. They will remember God's holy covenant and, having been rescued from their enemies, will serve Him without fear in holiness and righteousness before Him all of their days.