I seem to be hovering around verses 17 and 18 in Luke 2.
17 And when they saw it, they made known the saying that had been told them concerning this child. 18 And all who heard it wondered at what the shepherds told them.
If I had to land on a word in these verses today, it would be "wondered." But, not really. It's just that that word (perhaps through promptings by the Holy Spirit?), made my thoughts jump to the word "mysterious."
I read these verses and thought, "We wonder because our God is mysterious."
Here's how the dictionary defines "mysterious."
ORIGIN late 16th cent.: from French mystérieux, from mystère ‘mystery.’
I do see aspects of God described in this definition, although I would tweak them a bit. He is, on the one hand, difficult to understand, and on the other hand, a child can know him. He is impossible to understand, explain or identify...completely. I would definitely have to add the word "completely."
He is deliberately enigmatic. And yet, that doesn't short us in any way. We are told that we have all we need for life and godliness. Everything God does, He does deliberately. If He is deliberately enigmatic, it is for good reason. It is a call to trust.
We will not know everything we think we want to know on this earth. We have to make peace with the mystery. We have to embrace God's mystery.
We have to remind ourself that ultimately, the mystery is there for His glory and our joy.
And, our wonder.