When I first looked at this, I eventually decided that the flames were kind of magical and had traveled along that shimmering pathway. The logs maybe were, or weren’t people, and it had to be religious because of the cross in the background. So I went to research Gethsemane, and it started to make more sense. Gethsemane was a garden on the Mount Of Olives where Jesus went to pray the night before he was arrested. According to one account, he really didn’t want to die, so he was praying about whether he should do what his Father told him to do, or if he should follow his own, childish will.
Finally, he decided to let them kill him, and when the soldiers came with Judas to arrest him, Judas kissed him on the cheek (Judas Kiss) to indicate who Jesus was. The guards asked him if he was Jesus of Nazareth, and he said, “I am he.” This is apparently the same thing the burning bush told Moses, indicating that the bush was the voice of god.
Well, the fire, then, is the burning bush. The path is travels on could be the history from Moses to Jesus. It is the voice of god speaking to Jesus. The cross is the cross he will be crucified on, or the cross on the church on the Mount of Olives (apparently there have been many churches over the years, but there was one back then, although it must have been a synagogue or perhaps a roman place of worship).
The logs could, as @Dog suggests, be representative of various thoughts in Jesus’ head that night. One is more obviously human than the other. The less human one looks sort of comforting. The human one is on one elbow, as if lying around the fire one night, shooting the shit until you fall asleep. Neither seem to represent the anguish Jesus was supposedly going through that night.
I’m not convinced they are meant to represent Jesus. If so, I don’t think they do a good job of it. Like I said, to me, one isn’t even human and the other looks very relaxed, like it’s having a good time by the fire.
The logs themselves suggest both naturalism and manufacturism. They are cut down, as if being logged, and they could be about to be fed into the fire, or they could symbolize a kind of rape of nature. Cut logs don’t grow, and are a kind of static thing. A curious emblem for Christ, if that is what they are.
The sky is dark and threatening except around the cross, suggesting the gathering storm in which only the cross (church) is safe.
From a non-religious perspective, it seems like it’s about darkness and light. I get a sense of these forces competing, although I’m not sure the competition really matters, because there aren’t really any humans there. There is that cross in the background, but it is an ominous thing. It feels like it’s coming to get you, like some kind of zombie in the background.
The coolest thing in the painting is the fire. This is painted lovingly, and it portrays enormous energy. It seems to dance, and it could almost conceal a figure inside it, as if it was a human fire. It has flown in along this path as if on a magic carpet. It is supernatural, yet it contains a human kind of happiness. It has so much more energy than anything else in the painting. If it is on a magic carpet, you want to hop on and go for the most exciting ride of your life!