A contract is binding if the consideration involved is a commitment not to do something, as opposed to a promise to do something.

Consideration

In contract law, something of value given by one party in exchange for something of value from another party, forming the basis for a contract.

Binding Contract

An agreement between parties that is legally enforceable in a court of law.

Commitment

The state or quality of being dedicated to a cause, activity, or undertaking.