It is also a civil contract, as Chief Justice Waite stated when he delivered the courts opionon in Reynolds v United States.
Marriage, while from its very nature a sacred obligation, is nevertheless, in most civilized nations, a civil contract, and usually regulated by law.
The admendment is neccessary to prevent an activist judge from imposing a new civil contract on the federal government against the will of the people.
Statutory license... a function of the legislative branch of government...
“…In our opinion, the statute immediately under consideration is within the legislative power of Congress.”
It is not a function of the court to legislate....