One summer when I was about 12 or so, Dad took us exploring in the mountains out Hyndman. As I recall, we were quite familiar with one wilderness route in that area, but he was interested in discovering another. We didn't get lost per se, because Dad was so great with directions and he brought a topo map, but we definitely did some meandering. And he definitely spent some time staring at the map muttering and scratching his head.
At one point, in order to get back on track, we had to cross a huge snowfield on the side of a steep hill. There was a goat trail of sorts, and it was slippery. And I slipped. Then I slid maybe fifty feet or so down the snowfield. It was summer, so the snowfield was crusted over with a thin layer of ice, and I had a hard time stopping myself. But finally, I was able to dig my heels deeply enough into the snow to slide to a halt, about twenty feet from the edge of the snowfield.
When I tried to move to turn around, I slid some more. So then I just sat. Stuck. Dad used his extra calm cheerful voice to try to coach me back up the snowfield, but I was too scared to follow his instructions. Finally, my brother, Tony, came to my rescue. He made his way down the snowfield to me, as cheerful as Dad. I think he even said something like, "Wheeee! This is fun!" to put me at ease. Then he gave me step-by-step instructions to get myself turned around and headed back up. Then he climbed with me, slightly behind me, ready to catch me if I lost my footing once more. We made it back to the rest of the family on the trail, and we all made it across the snowfield, and all was well.
I later learned that at the bottom of the snowfield was a big ol' cliff, and if I had kept sliding, I would have slid right off the cliff and, you know, smack. Died at the bottom. Dad knew that. Which was why he used his extra calm cheerful voice the whole time. Because he knew that if I panicked, I would decrease my life expectancy.
Tony also knew there was a cliff. But he came down the snowfield anyway. He risked his own life to save mine.
This is love.
So... you're me, sliding down a snowfield toward impending doom. Tony is Christ, coming after you, sacrificing his life to save yours.
That's why Jesus came down to earth. That's what Christmas is all about.