I would use a lip chain on him. I might also carry a dressage whip and smack him until all his feet were on the ground again. Assuming there is no medical reason for this behavior. Rearing is dangerous and I don't tolerate it. The lip chain should give you a lot of leverage by itself if you think hitting him or her with the whip might just add to the frenzy.
The general answer is to figure out why he is rearing -- most likely because of something you are doing or not doing -- and fix it, while working on general communication and groundwork.
This is not a useful answer in your situation, I suspect, because presumably if you *knew* why it was happening and *knew* how to fix it you would have done so and not be asking the internet
Thus I am going to second michickenwrangler's advice of get a GOOD TRAINER to help you. I would not suggest a lip (or any other) chain without knowing why he's rearing, as depending on the reason and what you'd do with the chain that can potentially make matters worse.
I would seriously SERIOUSLY not advise "smacking him with a whip til his feet are on the ground" as this will not actually teach him anything other than to fear/distrust you AND a significant number of horses will take it as "fighting words" and actually come after you. Which is quite dangerous and definitely not in the *slightest* helpful in SOLVING your problem.
Really. Trainer. Possibly someone of a 'natural-horsemanship' type, who will work on communication and groundwork. Clearly there is a MAJOR lack of constructive communication going on, and you need to find someone to help you fix it before you get kilt.
In the meantime, try to avoid leading him in circumstances where he is likely to rear, as much as possible.
Rearing is a serious, dangerous problem and unless you know EXACTLY what you are doing, please don't *try* anything on your own. Especially if this horse is trying to "thump" you.
Rearing is dangerous and you don't want to make a mistake here. You need a professional to help you out. By the way, a professional does not hit the horse, does not hit the horse over the head, lip chains will only make a horse go up as he will try to go up to get rid of the pain. Is the horse a gelding or a stallion. How old is it? Green, or trained? Horses need calm, consistent handling by confindent knowledgeable handlers. If you're unsure, not confident and trying to handle a young, green or dominent horse you will get hurt. Good luck, and check out natural horsemanship websites so that you can find a reputable trainer.
I would lunge him every time he rears, just get him moving, and once he starts dropping his head and listening to you, start walking agian, and if he does agian, repeat. But be careful.