Okla. Stat. tit. 15, § 15-107: Moral or legal obligation on promisor good as

consideration.

An existing legal obligation resting upon the promisor, or a

moral obligation originating in some benefit conferred upon the

promisor, or prejudice suffered by the promisee, is also a good

consideration for a promise, to an extent corresponding with the

extent of the obligation, but no further or otherwise.