I started with the first verse in the list of verses you showcased as evidence in the link you shared. I made no more of a big deal out of than the link. I just showed how it was a reference to the entire body, and not the individual.
We do choose to soften and harden our hearts. As we are tested, we can make choices that make us worse or better.
Acts 16:14
New American Standard Bible
First Convert in Europe
14 A woman named Lydia was listening; she was a seller of purple fabrics from the city of Thyatira, and a worshiper of God. The Lord opened her heart to respond to the things spoken by Paul.
This verse does not prove or disprove OSAS.
It states what all Christians believe. That God searches the hearts of mankind. Those pursuing his righteousness will be drawn near to God. While those pursuing evil he will turn a deaf ear towards.
1 Corinthians 6:16-20
New American Standard Bible
16 Or do you not know that the one who joins himself to a prostitute is one body with her? For He says, āThe two shall become one flesh.ā 17 But the one who joins himself to the Lord is one spirit with Him. 18 Flee sexual immorality. Every other sin that a person commits is outside the body, but the sexually immoral person sins against his own body. 19 Or do you not know that your body is a temple of the Holy Spirit within you, whom you have from God, and that you are not your own? 20 For you have been bought for a price: therefore glorify God in your body.
This is another great set of verses to support my view as a biblically based view. In 1 corinthians 6 it compares Christians, the body of Christ , as a bride. As in a marriage. It says the one who joins with God is one with him.
Then immediately in the next chapter, 1 corinthians 7, it talks about marriage. But it also talks about divorce and remarriage. It brings up justifiable causes for divorce. So those verses can definitely be used to illustrate the just causes that God has to divorce from his bride. If the individual is not faithful, but adulterous towards God you will be divorced from him and cut out.
Being āunboughtā is essentially the same as being put away which the Torah mentions as the result of some marriages.