Again thanks for the discussion.
IMHO, if a couple, with the blessing of their parents, vow to each other, and to God, to join together as one in Christ, legal ceremony or no ceremony, are married in the eyes of God.
Why would they have to vow to each other.
I read that the Roman ceremony involved saying certain words in front of a pagan priest (maybe priestess). In their case the bride would say, "Where you are Gaius, I am Gaia" or something along those lines. So some Romans convert to Christianity, change out the pagan priest for a Christian elder, and change the words from the previous words to some kind of vow. Where does the Bible teach that a vow makes the marriage?
The Bible speaks of covenant, but the groom in the Old Testament would pay a bride price. How does that mean he had to make a vow to his bride to be married?
My point is we should not assume our cultural rituals are universal requirements.
When Boaz got married, he was marrying a widow, so he dealt with the one before him in line as kinsmen redeemer with ten elders present. We can read the words he said in Ruth 4, but there is no reference to his making a vow to Ruth to marry her.
8 Therefore the kinsman said unto Boaz, Buy it for thee. So he drew off his shoe.
9 And Boaz said unto the elders, and unto all the people, Ye are witnesses this day, that I have bought all that was Elimelech's, and all that was Chilion's and Mahlon's, of the hand of Naomi.
10 Moreover Ruth the Moabitess, the wife of Mahlon, have I purchased to be my wife, to raise up the name of the dead upon his inheritance, that the name of the dead be not cut off from among his brethren, and from the gate of his place: ye are witnesses this day.
11 And all the people that were in the gate, and the elders, said, We are witnesses. The Lord make the woman that is come into thine house like Rachel and like Leah, which two did build the house of Israel: and do thou worthily in Ephratah, and be famous in Bethlehem:
IMHO, unless the couple has made a vow to each other and to God, they are only (for lack of a better term) shacking up.
Have to swear a vow to be married? Where do you get that? Jesus said 'Swear not at all.' So are Quakers and Amish not married? And what about Adam and Eve and most Jewish couples up through the first century? Were they not married?