We will have differences of opinion for those sealed in Christ by the Spirit vs those who aren't. Paul is not stating Christ will remain faithful to Himself which is self-evident to all who belong to God.
Those who know really know Christ would know this.
Simon Peter answered him, “Lord, to whom shall we go? You have the words of eternal life.
69We have come to believe and to know that you are the Holy One of God.
Can not and will not.
No one who is born of God will continue to sin, because God’s seed remains in them; they cannot go on sinning, because they have been born of God.
You don't start with the Spirit and finish with good works. Its grace through faith.
You love one another as Christ loved. That fulfills all the law. Love does no harm to one's neighbor.
We who are sealed in Christ by the Spirit have been chosen by God. We have been appointed to eternal life by God. And He will remain faithful to that appointment.
Jesus stated Never perish which can't be true in your theology. For you believe one who has been sealed in Christ by the Spirit and are one with Him could possibly perish if they change their mind which would be madness as they would know and believe Jesus alone is life without end and apart from Him is death without end.
I give them eternal life, and they shall never perish; no one will snatch them out of my hand
I don't view this as OSAS I view it as grace.
Paul who was set apart at birth before he did good or bad knew about grace and never backed down.
God has the ability to keep us safe in the most sinful of environments.
And what was God’s answer to him? “I have reserved for myself seven thousand who have not bowed the knee to Baal.”