I have been reading Galatians. I believe sanctification is a continual process. That there is a moment in time salvation occurs, and it is continual as God sanctifies us. I believe God chooses whom he wants, but moreso I believe we have all been called by God and are all written in the book of life. I believe at the moment of salvation we accept God's choice, once and for all, and we accept then the promises of God. One thing about the promises of God, is that no matter how many times we break our end of the deal, God is still faithful, lest he be called a liar. The Jews broke their end of the covenant continually but God was faithful to Abraham, who was declared righteous by His faith, and to whom the promise was given. When we are born again, it is not like being adopted in a sense we think about today. We are born in spirit into the family of God, as his very own children. A child of God born into his own family, cannot be not a child of God any longer as seen in the story of the Prodigal son. I believe there is no requirement to act as a child of God for the purpose of our salvation after our salvation, but we are encouraged to respond to the grace we have been given by God, and we are privileged to work cooperatively with God to benefit His kingdom. Truly, we have lost sight of God if our works do not prove our faith; it can even be questionable whether there was a moment of salvation to begin with, for it is a sign to everyone except God, that works prove the work that the Holy Spirit is doing in our lives; God needs no proof. What we have left then is our identity in Christ which is irrevocable, the benefit of which is the exhortation and building up of the body of Christ and loving one another which is our sign to non believers of Christ's work in us.
When are we actually considered children of God? I think is the question everyone is asking. I'll try to keep studying to figure out what I believe. I have assumed it is the moment of salvation, when we first choose to become the children as God originally intended. I understand God can turn rocks into children of Abraham, but is us he chose, and it is only by God's grace we each have been given a portion of faith that if turned to God we can be declared righteous in His eyes. And God's promise to Abraham of Christ Jesus came before the law was given, the law which was full of conditions.
The Prodigal son lost something did he not.