For me, the Christmas spirit is palpable; like a vapour which seems to inhabit the air at increasing concentrations over these weeks approaching the date.
Yet I am very unsure about what it is, or even why.
Nothing actual about Christmas seems to come close to defining what the spirit is; because of the mystery of Jesus.
I find Jesus a deeply mysterious... phenomenon. He is at the centre of our faith, but the reason cannot be pin-pointed - because it seems on the one hand no reason fully captures it; while on the other there are too many reasons.
For most people on Earth, Jesus is either just one of many similar spiritual exemplars; or just an optional extra to, or distraction from, the primary and necessary work of God - for Christians he is central, but we can't say why in any concise fashion. The New Testament authors grapple with this question in many ways.
The birth of Jesus was a cosmic event, and Jesus was a human baby - everything Jesus did or said seems to raise as many questions as they answer. If he was necessary why was he local; since he was saviour, how come he brought sharp choices? He is our King and our brother; of astonishing power and status, and the close companion of the humblest and the worst of people.
We try to bring system and clarity to these matters - but the systems are too loose as well as too contrived. Yet lack of system seems to let us off the hook and sets us adrift, or spiralling downward.
It is all too much for human reason - and in the end a child, the ignorant or the fool make as much - or more - sense of Jesus as the eloquent, the learned, the disciplined...
All this is brought out at Christmas with the greatest clarity, by the Nativity story, the prophecies, the foreknowledge of what happened afterwards, the setting so remote in time and space: yet brought very concretely alive in the specific instance of our own specific, modern church and family.