My boss will not let me quit my job! What do I do?

I have been working for a company for a few months, and when I was hired it was agreed that I would work for my current employer until I found a full time job. Now that I have found a new job, I have professionally provided my two weeks notice, and I am preparing to complete tasks so everything is left in order upon my departure. However, my boss will not let me completely quit my job. He is convinced that he can persuade me to work part time and does not respect anything I say. I have told him that I will train another employee to do successfully complete my tasks and he is still not satistified. His method of manipulation is the primary reason I am leaving this job, I am tired of dealing with it. I am trying to be pleasant and respectful with him as I develop ways to ensure him that I will not be able to work for him at all, because I want to focus primarily on my new job. He is breaching the terms our initial agreement. What do I do or say for him to leave me alone?