There is a big difference between a bribe and an incentive. An incentive is offered before the action is done while a bribe is offered after the child does something wrong.
For example, if you want to take your kid to the grocery store, if before you go yo tell your child “If you are good you will get a prize when we get home” that is an incentive. A bribe is when the child starts screaming in the store because he wants candy and you tell him that is he stops you will give him a prize.
An incentive is effective for behavior modification. A bribe only shows the child that by screaming or doing something wrong, he gets what he wants.
In the case brought up by the OP, I’d say it is a bribe because it was only offered after he refused to go to shul. Also, the skipping school part is not so good.