Legal Question in Credit and Debt Law in Massachusetts

Is a promise a legally binding contract?

Not from what you described.

What you have is merely a notarized promise. It could be remotely enforceable under a few circumstances, but there is no guarantee.

A promise is most often not a binding contract.

Re: Is this legally binding?

I guess it would be easier to answer this if we knew which person you are and what you are attempting to do. Are you the person who promised to make the payments and no longer wish to do so? Or are you the person on whose behalf the payments were being made, and you want to keep the payments coming? From your brief description, unless there was a benefit to the person who took on the payments (legal concept of consideration), the promise is most likely not enforceable. If there was some sort of benefit, then you really killed two birds with one stone: not only could this be an enforceable contract, you have also satisfied another requirement called the Statute of Frauds (which requires sureties, or promises to pay debts on behalf of another, to be in writing). Feel free to e-mail me with more details.