Advent is the season in which we celebrate waiting for Jesus's coming. The season is therefore significant to our entire entire lives: the life of a Christian is a life of active and striven waiting. Christ came, and Christ comes. Christ came, and is come. Christ came, and will come again.
All the Advent Scriptures we read hinge on waiting. What do we wait for when we wait on the Lord? Deliverance. Salvation. Deliverance from death. Salvation from death.
We are waiting on life. Life in the face of death, life through death.
The Christ came, as promised, and brought the good news that there is life, and life everlasting. He was born, lived a life, died, and lived again. The good news is that he came as the firstfruits of true life. He comes as the deliverer of this life.
How do we respond to his coming, if we believe? Well, there's an initial answer. He comes, we believe. But after that? Jesus came, and he had a message: "Come." (John 5, 6) How do we respond to that?
The last chapter of Scripture illuminates this for us.
In Revelation 22:16 Jesus speaks, saying that his message has been for the Church, and describing himself in the sort of Messianic language that is in our Advent readings: "I am the root and the descendant of David, the bright morning star." He is the inauguration of a new age, a new kingdom, the fulfillment of promises. He came to install and proclaim his Kingdom, saying "Come."
The response in the next verse is from the Spirit, and from the Church, and finally, from any one who desires to respond.
"The Spirit and the Bride say, 'Come.' And let the one who hears say, 'Come.' And let the one who is thirsty come; let the one who desires take the water of life without price."
The spirit of Advent and Christmas is an evangelistic one. Christ came, saying "Come". The Spirit of God and the Bride respond, saying "Come". You, the hearer, respond, not only by believing, but by saying to others, "Come".
Advent is the time of calling. Christmas is the time of calling. We are come to say "Come". Come one, come all.
Good tidings we bring, for you and your kin. We came here to tell you about him. Now you come out here. Come meet us, and bring figgy pudding and beer. Come fellowship with us. And we won't go until we got some.