Thomas Brooks asserts that sanctification is simply a living out of one’s adoption and sonship (John 1:12; Rom. 8:17). He writes,
If thou art a holy person, then of a child of wrath thou art become a child of God, a child of love; and of an heir of hell thou art become an heir of heaven; and of a slave, thou art become a son.
The Puritans would resonate well with J.I. Packer’s assertion that sanctification is,
simply a consistent living out of our filial relationship with God, into which the gospel brings us. It is just a matter of the child of God being true to type, true to his Father, to his Saviour, and to himself. It is the expressing of one’s adoption in one’s life. It is a matter of being a good son, as distinct from a prodigal or black sheep in the royal family.
Through sanctification the believer is brought into a fuller experiential awareness of his adoption. He learns to grasp more fully what adoption is, and learns to live out of its wonders