At the very first Christmas, God became man.
When you think about it, this is perhaps the most powerful truth of the Bible’s message. It’s at this point that everything else about the gospel stands or falls.
People tend to critique the gospel message’s claims about a virgin mum, seriously ill people being made well again, the raising of dead people back to life, and a death that has cosmic significance. This stuff just doesn’t make sense to reasonably intelligent people if Jesus was simply a first-century itinerant Jewish rabbi with messianic ambitions and high ethical standards.
But if he is actually God…?
Bible teacher and writer J.I. Packer puts it like this:
“Once we grant that Jesus was divine, it becomes unreasonable to find difficulty in any of this; it is all of a piece, and hangs together completely. The incarnation is in itself an unfathomable mystery, but it makes sense of everything else that the New Testament contains.” 
One of the carols we sing every Christmas puts it really well.
Christ, by highest heaven adored
Christ, the everlasting Lord,
Late in time behold Him come
Offspring of a Virgin’s womb:
Veiled in flesh the Godhead see,
Hail the incarnate Deity
Pleased as man with man to dwell
Jesus, our Emmanuel
– where “Emmanuel” is a word from the Old Testament which simply means “God with us” (Isaiah 7:14, Matthew 1:23)
Live it: As we celebrate Christmas, let’s remember that what we celebrate at this time of year – God becoming man – is the key that unlocks the entire gospel. Let’s believe it, and celebrate it.
– Clint Lombard
- p.59, Knowing God, by J.I. Packer (c) 1973, Hodder & Staughton