Define marriage a little better.
A covenant betwixt a man and woman that is taken before a Minister and God.
There are some "ministers" that are not ordained, or are not licensed by the state to perform a marriage.
My wife and I were married by a CoC preacher, and he was "ordained" via the state of Kentucky. He even had the "seal" to put on our marriage certificate.
If a marriage by today's standard are the vows that unite a man to a woman and those vows are taken in the presence of both man and God according to the laws of the country, then it is possible that the marriage could be constituted as a sin.
How so? Please expound further. Tracy and I were married before both our families, the CoC minister read some scriptures about the marriage bed, amongst other verses, my dad and father-in-law signed our certificate as witnesses, so I think that's the biblical way. I know you weren't questioning my marriage, I was just throwing it out there to show you I know what I was talking about.
But, like Aaron, I am not sure what the purpose of your post was.
I have read where some say that everything a sinner does is a sin. If so, marriage falls under the "umbrella" of everything, so by mere implication, two sinners marrying, doing so in accordance with the bible, would still be sinning, no? Maybe I am thinking wrong, but I think not....that's why I am throwing this out to get y'alls opinions.