What it means to be God's children

“The adopted status of believers means that in and through Christ God loves them as he loves his only-begotten Son and will share with them all the glory that is Christ’s now (Rom.8:17, 32, 38-39).

“Here and now, believers are under God’s fatherly care and discipline (Matt.6:26; Heb.12:5ff.) and they are directed, especially by Jesus, to live their whole lives in light of the knowledge that God is their Father in heaven, praying to him as such (Matt.6:5-13), imitating him as such (Matt.5:44-48; 6:12, 14-15; … Eph.4:32-5:2), and trusting him as such (Matt.6:25-34).

“[In living this way they express] the filial instinct that the Holy Spirit has implanted in them (Rom.8:15-17; Gal.4:6).

“Adoption and regeneration accompany each other as two aspects of the salvation that Christ brings (John 1:12-13), but they are to be distinguished. Adoption is the bestowal of a relationship, while regeneration is the transformation of our moral nature.

“Yet the link is evident; God wants his children, whom he loves to bear his character, and takes action accordingly.”

-- J.I. Packer “Concise Theology” pp. 167-168 (Tyndale)