I read "outrageous", "rear" & "arab".
Other folks suggest:
Going back to basics, with poles on the ground.
Trotting up rather than cantering
Lunging over the poles
then lunging over slightly raised poles
These moves must all be part of the re schooling. For sure.
But what about your hands - are you absolutely sure you don't jab on his mouth when you are over the jump??
Do you jerk him as you take off?
Are you riding him on contact or on loose reins?
How solid is your seating position?
Does the saddle fit properly?
And do you get angry??
Arabs as a breed are intelligent and sometimes cussed.
He will pick up on your anger - and as for whips --oh - never.
If he was jumping before for the previous owner, and if of course he/she was telling the truth, then perhaps the problem lies with his relationship with you - or rather yours with him.
Was he leased out to someone else before you got him?
You can check all this out by getting a competent friend to try him over the jumps. If she can do it and you can't then - well, she can show you how.
It might also help you, if a friend took a video of your riding the jump.
You could also work together with the friend in the arena - she goes first at the jump on her horse, you follow not too far behind.
But if an arab is rearing, then for sure he is not happy and until you isolate exactly why, you'll get nowhere.
Nice kind words like "good boy" "come on son" - not necessarily in arabic , help. But never say "outrageous" to a horse, even in English.