For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
In a nutshell, Scripture teaches that God saves, or delivers us, from sin [disobedience], not in sin. Jesus recalled the divinely mandated position on marriage in the Genesis account. In effect, He was endorsing a divinely established policy: one man and one woman. Who dares to secularize the policy of a God who, in laying out His policy, saw the end from the beginning?