Marriage is a social estate, created and preserved by God. It is between one man and one woman exclusively. Jesus reaffirms this in Mark 10:6-9. After the fall and exile from the Garden humans have altered and formed their own constructs in defiance to God's original design. It is the nature of sinners to do this. Even divorce is against God's design as it only came about through a command from Moses (and not God). There may be marriages created by human societal orders (ie. USSC) which make it a societal norm for same-sex marriages. But this too is against God's design.
I'll remind you again, that the Old Testament does not have a word for "marriage." Rather, the Hebrew uses possession terms; usually, "to take a woman" to describe the transference from father to husband. The only word for husbands (besides "man") is ba`al, which means "to rule over" or "to own/possess". Thus, whatever relationship the first humans had in the garden, and the humans afterwards, was not seen in the same way that we view "marriage." The only words they used to describe the relationship was those related to property ownership.
So what order is Jesus describing in the Mark 10 passage? Certainly he recognizes a certain estate into which one man and one woman enter. Btw...what happens to this construct after the fall and exile in the Garden is always malleable so that humans can create situations which might be acceptable between or among them. Sinners do this but never with God’s okay.
Also, why is divorce bad? If marriage is just a matter of falling in love with someone and wanting to spend the rest of your life with that person, then why shouldn't people who fall out of love with each other and no longer want to spend the rest of their lives together not be allowed to do so? Once you remove the whole idea of the two becoming one flesh, which people of the same sex cannot do, and utterly divorce the roles husband and wife from the roles of father and mother, there seems to be precious little reason to bother with marrying or recognizing marriages at all. Why should society care who wrote "BFF" in whose yearbook?
Among other reasons, divorce is bad because the two people made promises to each other and now they are breaking their promises. All the vows I offer to couples include a life-long commitment to each other.
Perhaps the most influential book for me I've read on marriage is
The Sex Manual for Puritans, by Vernard Eller (© 1971 Abingdon Press). What I remember is that the basis for marriage is not love (or sex,) but
commitment. The
feeling of love within a marriage will go up and down.
Experiences of sex may wane or become impossible because of health conditions. What a couple promise each other is to be committed to each other through all the good and bad times; the great moments of love (and sex) and those times when neither seem to be present.
Marriages end when one or both parties are no longer committed to the other.
And yes, Jesus was clear that because of human sin, namely, "hardness of heart," divorce laws are necessary. As I've heard a few people say, "Divorce is better than murder."
While George Rahn is right concerning Jesus' view that Moses (not God) gave the divorce law. Deuteronomy is clear that Moses is speaking for God in giving all the laws, e.g., "But watch yourself! Don’t forget the Lord your God by not keeping his commands or his case laws or his regulations that I am commanding you right now." (Deut 8:11, CEB)
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