At dusk

[Fae]

I'm not 100% sure on what this poem means, but I do think it has some interesting themes. The idea of nature going into hiding when night arrives, contrasted with the strength of the last line, kind of makes me think you're creating somewhat of a commentary on how the human spirit can survive "night" as in, the feeling of a bout of depression coming on, adversity, and the likes. You could really expand on this, though this is just my interpretation of the poem. I read you mentioned the last line being about faith, so that's kind of how I've interpreted your poem based on what you said. I could be completely wrong though, as I'm a beginner when it comes to critiques and poetry in general. Anyways, here are some of my nit-pickings

At dusk
the leaves are bending.   
(I'd maybe go with shrinking, or shrivelling here instead of bending, though as somebody else pointed out "the branches are bending" would work if you really wanted to keep that word in there)                               

They are fading away.
The light they are closing. (maybe something like... with the light, they are closing - I see them fade away.)

Under the ground
I won't be. (after redrafting and creating other edits of this, you could without a doubt use this

I think you're trying to create a simple poem that has alot of punch. Personally, I find it difficult to explore deep concepts in a simple way like this, so I would say this takes alot of balls, braver than anything I'm attempting at this current time. I'd try and use this poem to write a longer one, then I'd cut down that longer one so that they go along with the themes and message of this draft, and go from there.