If we want models for Christian art that speaks truly and deeply, giving no concession to sentimentality, I nominate Dürer.
He not only gives us a stable, but a total wreck. I love the timbers balanced precariously above the courtyard, and the window swinging on its hinges in the room above baby Jesus. How many pigeons live in there? The plaster crumbling off the exterior and the trees growing out of the ruins in the background are also marvelous atmospheric touches.
But the thing that grabs me in this engraving is the fact that I have to hunt for Jesus, Mary, and Joseph. The figure in plain view is that of an old man preoccupied with pouring water into a too-narrow jar. In the stress of his task, he seems unaware that God is just up those neglected steps.