The first Act of Advent is Adoration, adoration of God who in Jesus Christ has enacted his great and lasting promises to Israel.

Why is the first Act of Advent Adoration?

First, because Jesus is the Savior — the one who liberates people from their enemies and their sins.
Second, because Jesus is the Messiah, the Lord — he is the aim of Israel’s history and the one who rules over all of history.
Third, Jesus brings peace — for the world.
Fourth, the sight of the Christ child was the cause of wonder and worship.

Again, Christmas is about Jesus and our first posture is one of adoration. Let us adore.

Luke 2:8 And there were shepherds living out in the fields nearby, keeping watch over their flocks at night. 9 An angel of the Lord appeared to them, and the glory of the Lord shone around them, and they were terrified. 10 But the angel said to them, “Do not be afraid. I bring you good news of great joy that will be for all the people. 11 Today in the town of David a Savior has been born to you; he is Christ [fn1] the Lord. 12 This will be a sign to you: You will find a baby wrapped in cloths and lying in a manger.”

13 Suddenly a great company of the heavenly host appeared with the angel, praising God and saying, 14 “Glory to God in the highest, and on earth peace to men on whom his favor rests.” 15 When
the angels had left them and gone into heaven, the shepherds said to
one another, “Let’s go to Bethlehem and see this thing that has
happened, which the Lord has told us about.”

16 So they hurried off and found Mary and Joseph, and the baby, who was lying in the manger. 17 When they had seen him, they spread the word concerning what had been told them about this child, 18 and all who heard it were amazed at what the shepherds said to them. 19 But Mary treasured up all these things and pondered them in her heart. 20 The
shepherds returned, glorifying and praising God for all the things they
had heard and seen, which were just as they had been told.