A child who is adopted into a new family is basically given a new birth
I can not be a sin unless I am
Adopted
I Can not have Every spiritual blessing in Christ unless I am
A son I can not be a sin apart from adoption
You are correct, for If we were not adopted, why does the Spirit give us utterance to cry ABBA, Father.
Yet, There is also a sense in which the adoption is declared at our resurrection, but yet we are already sons of God. Just as Jesus was God’s Son and yet was declared to be the Son of God in the Resurrection. (Romans 1:4) ( of course, it’s different because Jesus is not adopted, but is Son by nature not adoption)
Yet He was powerfully demonstrated to be the one and only UNiQUE SON by the resurrection. It did not then become fact, it was powerfully declared to be fact with the biggest exclaimation point ever written.
And as adopted sons of God, we have the hope of resurrection, which is the manifestation of the sons of God.
As it is written in Romans, we ourselves groan waiting for the adoption, to wit the redemption of the body.
So we are already sons of God (1John 3:1), but there is a greater realization of that fact in the resurrection of our bodies, when we will bear and wear the image of the heavenly?