Help - white horse imagery - Elliot's Journey of the Magi

I'm going to participating in a reading of Christmas literature, including T. S. Elliot's Journey of the Magi, a poem that I love. There is one image I can't wrap my head around so I thought I'd post here asking for your thoughts/interpretations.

The complete poem is here.

The old white horse reference appears in the second stanza where there are many images referencing events/words in the Gospels:

Then at dawn we came down to a temperate valley,
Wet, below the snow line, smelling of vegetation;
With a running stream and a water mill beating the darkness,
And three trees on the low sky,
And an old white horse galloped away in the meadow.
Then we came to a tavern with vine-leaves over the lintel,
Six hands at an open door dicing for pieces of silver,
And feet kicking the empty wineskins.

Click to expand...

Much of the criticism I found on the web skipped over this reference completely while IDing the crucifixtion, the soldiers gambling for Christ's robe, Judas's payment, and new wine in old wine skins. I did find a couple linking the horse to the image of Death in Revelation and one stating that it clearly meant the triumph of Christ over Death. I'm having trouble wrapping my head around those because it doesn't really flow with the speaker's thoughts about death in the final stanza. And it seems odd that all the other references in the second verse come from the Gospels. (Yes, I know that Christ triumphs over death in them but it still means that I have to travel all the way to the end of the NT to find the white horse image.) Maybe I'm over analyzing it. Any thoughts? Any horse images in the Gospels that I'm blanking on?

Thanks for any feedback you can give.

Never mind - x-posted to pagan and crit theory. pale/white horses part of celtic lore. Narrator of poem sees three trees representing crucifiction and then the old white hose (representing the old religion) moving away from him.