But you are leaving out the rebirth, regeneration, born of God, which is not by the will of man. Man only receives the gift, the call of the Holy Spirit to submit and allow God to do His will in the new birth.
God never granted a divorce. He allowed Moses to grant divorces for the purpose of mercy. Jesus said it has always been one man and one woman for life. This is another reason to understand OSAS, as you point out, it is a marriage with Christ and this cannot be broken by man or God.
"He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so." (Matt 19:8)
Even if two who are married divorce by a written decree from a state, through the eyes of God they are still married, however separated. And if they remarry, they live under a state of grace and mercy granted by God for their adultery.
I believe the bible emphasizes we partake through the Spirit within that cries ABBA Father. (Romans 8) If we say it is just by believing the bible, what does that mean? Baptist understanding, Catholic understanding, SDA understanding?
This is why God had to make saved so very simple. Salvation is through calling upon Jesus Christ to save and God makes sure that the person who calls stays eternally saved. You don't get saved by grace through faith not of yourselves and then spend the rest of your mortal life trying to stay saved of yourself.
If only every sect of Christianity would hear the Holy Spirit through Paul's words..."
"But I fear, lest by any means, as the serpent beguiled Eve through his subtilty, so your minds should be corrupted from the simplicity that is in Christ." (2Co 11:3)