[Marzi]

The thing is that often biting gets a reaction - and for some dogs any reaction is a good reaction.
Your boy is a rescue and he has a lot of learning to catch up on, he is also not a baby puppy any more, he is entering thug puppy teenage stage when a lot of dogs test the boundaries.
Enough - is a good command and with my dogs means the end of the game or the end of excited behaviour. Say it firmly cross your arms and ignore him, if he backs off praise him very gently and give a treat if he will sit.
If he does not back off but just keeps jumping and biting at you and if you are confident to do it - I don't know what your expereince is. Catch hold of his collar one hand either side of his neck, under his ears, and hold him so he cannot jump, but he can sit (ie not down on the ground, that would be forcing him into a submissive posture and could well frighten him) at about your knee height. Look him in the eye and say firmly 'Enough'. Look at his eyes, the moment he glances away release and praise him. That glance to the side is him saying 'I don't want to get into a fight over this!'
You need to be absolutely calm and not remotely cross - don't shake him or grab his skin and hurt him, or use more force than to stop him jumping up. If your hands are in the right place he shouldn't be able to bite at them.
If he immediately jumps up and starts biting again repeat calmly and firmly.
I would not recommend this with a young pup, but your chap is no baby and he has probably enjoyed (rightly ) lots of love and indulgence since you rescued him. But enough is enough and he needs to kow where the line is.
My Dad used to breed GSDs and this was a technique he would use quietly and firmly to put an adolescent thug puppy very gently in his place - it is critical that you watch for that glance away, if you miss it and keep the force on you are putting your pup into a flight or fight place because you have not responded to his signal that he wants to back down.