The second O Antiphon sung in keeping watch for the Lord’s Nativity:

O ADONAI [God of the covenant] and Ruler of the house of Israel, You appeared to Moses in the fire of the burning bush, and on Mt. Sinai gave him Your Law: COME, and redeem us with an outstretched arm!

The following commentary adapted from The Church’s Year of Grace, Fr Pius Parsch (The Liturgical Press, Collegeville, 1959)

The Second Person of the Holy Trinity had an active part in creation, as was noted in yesterday’s “O.” Now the liturgy, seeing Christ in the perspective of divinity, finds Him active in the Old Testament. Christ was the “Covenant of God” of the Chosen People. He made a covenant with Noah, with Abraham, Isaac and Jacob, and with Moses; He was the ruler of the Jewish people through history; two of His many appearances are mentioned in tonight’s antiphon (the burning bush and the giving of the Law midst lightning and thunder). The petition associates the deliverance from Egypt with the world-wide redemption from the bondage of sin.

The “Exodus event” is one of the most important of all of salvation history. It began when God appeared to Moses in the burning bush, commissioning him to lead the Chosen People. This climaxed in the giving of the Law on Sinai. God showed Himself to His people as Defender and Redeemer, going before them “with an outstretched arm.”

This same “Exodus event” has always been regarded as a primary “type” of Christ’s work of redemption. Year after year we are brought back to these images and their fulfillment in the birth, life, death, and resurrection of Jesus Christ. And today Jesus wants to enter my soul, to be its Ruler and Lawgiver. Christian life means following Christ. Christ wants to be my Law; without Him, there is no Kingdom of God. He wants to redeem me “with an outstretched arm,” but can do so only on condition that I unite my will to His. Listen, O my soul, to His direction!