What does Mark 10:8 mean?
The men of Israel had a very liberal view of divorce. The second century BC Jewish scribe Ben Sirach wrote, "If she does not accept your control, divorce her and send her away" (Ben Sira 25:26). The historian Josephus reflected the mores of Jesus' day when he wrote, "At this time I divorced my wife, not liking her behavior" (Life 426).The Pharisees and the disciples (Matthew 19:10) are filtering a note in the Mosaic law (Deuteronomy 24:1–4) through an interpretation established by a school of scribes who lived about one hundred years earlier. The Hillel school interpreted the law to mean husbands could divorce their wives for anything they find odious. They conveniently ignored the fact that the law doesn't describe grounds for divorce in detail. The passage in Deuteronomy merely mitigates the damage of the unfair cultural tradition by saying the man must formally release his wife so she can marry again. And if she does remarry, he can't have her back.
Jesus asks about what Moses commanded, and the Pharisees think they are clever by challenging Jesus with such a well-established traditional view of a caveat in the Mosaic law. But they forget that Moses also wrote Genesis. Jesus takes them even further back, to creation and God's original purpose of marriage. The only time in history a single human being has been split into two individuals is when God took Eve, literally, but with powerful symbolism in the form of a rib, out of Adam's side. When Adam awoke, God immediately put them back together again (Genesis 2:21–24). This is the origin of "one flesh." To be one flesh is to be unable to split into two. Divorce doesn't separate two people, it rips a single entity into two broken people.
We should never analyze God's commands to see what we can get away with. Nor should we settle for scraping by on the edges of His provisos. We should always consider His intent which is always in our best interests.