With joy you will draw water from the wells of salvation.
And you will say in that day:
Give thanks to the LORD, call on his name;
make known his deeds among the nations;
proclaim that his name is exalted.
Sing praises to the LORD, for he has done gloriously;
let this be known in all the earth.
Shout aloud and sing for joy, O royal Zion,
for great in your midst is the Holy One of Israel.
Satan and the evil spirits hate the Incarnation (and incarnational reality) because in it the God of the Old Testament, He Who is faithful and full of loving kindness, is made present to our world. In Jesus Christ the full revelation of God is made present to man. This, as John’s Gospel shows, is a revelation of light, and to know Jesus is to know the Father and to walk in light. To be in sin is to be in darkness, and to fail to believe in Jesus is to remain in one’s sins and in the kingdom of darkness. This believing is manifestly an experiential knowing, a relationship with a Person, as Luther says, closer to us than we are to ourselves. 
Jesus has come so close, He is more wonderfully with-us than words can adequately describe. We aren’t told to rationally comprehend His coming, but to rejoice in it, to shout and sing in the freedom He brings. The presence of the One we love is the surest cause of joy, and the discipline for this third week of Advent is to cultivate that joy. We can’t force joy, but it grows as we adore and en-joy Him. Joy even grows as we welcome His light that illuminates sin and leads to repentance, as contrite tears yield to the joy of a cleansed and forgiven heart.
Jesus, You are the center of my life. You are the center of my being. I rejoice in my salvation, and in all Your glorious works. I rejoice in Your incarnation. I rejoice in the light of Your presence, and in Your victory over darkness and evil. I rejoice that You are coming again soon. Alleluia! I rejoice in praising You!
 Leanne Payne, Real Presence (Grand Rapids, Baker Books, 1995), p. 88.
Painting: Federico Barocci, 1597, The nativity [Public domain], via Wikimedia Commons
Meditation prepared by Sarah Colyn, drawing on the writings and ministry of Leanne Payne.