The deed of one should not hurt another.

Explanation

(English-origin maxim.) No person should be prejudiced by the deed of a stranger — the acts of one party cannot impose obligations or forfeitures upon another who is not privy to the instrument.

Where this applies

• A landlord signs a lease with a new tenant that includes a noise restriction, but the landlord tries to enforce that restriction against a neighboring tenant who never agreed to it.
• A husband takes out a personal loan and the bank tries to put a lien on the wife's separately-owned property — his deed cannot burden her title.
• One business partner signs a non-compete agreement and the other partner's competitor tries to enforce it against both partners — the deed of one doesn't bind the other.