The only way to be free from the slavery to fear is being adopted into the family of God. Retrospectively, if one is not part of the family of God, he or she will find herself enslaved. There is no in between. We are either sons & daughters of God or salves to fear.
12 So then, brothers,[a] we are debtors, not to the flesh, to live according to the flesh. 13 For if you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live. 14 For all who are led by the Spirit of God are sons[b] of God. 15 For you did not receive the spirit of slavery to fall back into fear, but you have received the Spirit of adoption as sons, by whom we cry, “Abba! Father!” 16 The Spirit himself bears witness with our spirit that we are children of God, 17 and if children, then heirs—heirs of God and fellow heirs with Christ, provided we suffer with him in order that we may also be glorified with him.