It may seem like marriage is simply a contract.
"I'll do my part; you'll do yours. If we disagree, we can compromise and still keep the deal (the contract) valid."
It sounds just like a contract statement.
But, there is an alternative view.
Contracts, Sacks said, are transactional, while covenants are relational.
With a contract, you agree to do X, as long as the other party does Y. If the other party doesn’t meet these expectations, or if a better offer or upgrade comes along, you jump ship. With a contract mindset, you extract the maximum value from an arrangement, and then move on.
With a covenant, you keep your commitment, even when the other party doesn’t seem to be living up to their end of the bargain, even when it isn’t convenient, even when you feel another arrangement would better meet your needs.
‒ https://www.artofmanliness.com/character/advice/sunday-firesides-covenants-over-contracts/