When it comes to jumping I have very little experience and knowledge. I know it can get very technical, the horse must get his steps in before the jump, you must sit correct and who knows what else, so if you want to go to shows, you probably shouldn't listen to me. However I think I can make a little contribution that you or someone else might find useful.
Once upon a time

there was a young girl who liked to jump her horse, however, this horse kept on refusing jumps, refusing probably about 4 out of 5 jumps. Later on I had a chance to ride the same horse. I decided I also wanted to try jumping with him. Set up a jump, he refused. I lowered the jump, he refused, lowered it again, he refused again, put the pole flat on the ground, he still refused. So this is what I did.
I left the pole flat on the ground. Worked him for 10 or 15 minutes at a trot and canter then took him to the jump (pole flat on the ground), just made him walk over the pole and let him rest on the other side. Trotted and a bit of canter round a few times and walk over the pole. When he started to realize that walking over the pole will result in a rest, I started setting up the jump. By the end on the session, I had him jumping one foot with no hesitation.
I'm doing the same with Frosty and she never jumped before I had her. I broke her in myself. And she is absolutely so keen on jumping. If I'm not paying attention, not steering, she will by herself head for the jump and hop over. I don't go higher that 2 feet, I just do it for fun.
So my suggestion would be to place a pole on the ground between the posts or tyres or what ever you would use to set up the jump and just work your horse a bit and then let him go over the pole and rest. Horses can jump naturally and if you give your horse a reason to jump (the rest) he'll do it. Just take it slow and keep the jumps low in the beginning. As mentioned, they also need to learn to get their footing right before the jump and in the beginning, with incorrect foot placing he could make a huge leap over a very small jump, so be careful. I don't really know how to teach a horse to pace themselves correctly before the jump, other than just letting them figure it out by themselves.
My point I want to make is give your horse a break after the jump and he'll get to enjoy it. Hope that will help someone out there.