Like Peter who took his eyes off Jesus as he walked on the water, we sink. We sink into questions about where lines are drawn and who has crossed them. But we could walk on water if we found ways to support each other in our daily efforts to stay near to the heart of God. We could walk on water if our eyes were fixed on Jesus, rather than thinking we can fix our lives by not stepping over the line. Jesus was right.
Divorce is a sin.
It falls short of God's ideal for marriage. At the marriage altar, we aim for a covenant of fidelity and love. However, some of us fail. It is a sin. Therefore, as Jesus says, Moses gave us legal guidelines to regulate divorce and remarriage.