“It is the Spirit of adoption who produces the highest confidence that is given to men to exercise in relation to God. The people of God thereby recognize not only Christ as their Redeemer and Saviour, high priest and advocate at God’s right hand, not only the Holy Spirit as their sanctifier and advocate, not only the Father as the one who has called them into the fellowship of his Son but also as the one who has instated them in his family, and they enter into the holiest in the assurance that he, the God and Father of the Lord Jesus Christ, will own them and bless them as his own children. No approach to God partakes of comparable intimacy, confidence, and love with that of the simple, yet unspeakably eloquent, ‘Abba, Father.’” (Collecte Writings of John Murray, Vol. 2, pages 229–230)
“The covenantal gift of adoption in the Old Testament points to the Christological gift of adoption in the New Testament, when the Spirit who applied God’s filial favor to Israel corporately in the former epoch is given in full measure in the resurrected Christ Jesus in the inaugurated eschatological epoch,” (David B. Gardner, Sons in the Son: The Riches and Reach of Adoption in Christ, p, 160)
“But if faith regenerates us, so that we are the sons of God, and if God breathes faith into us from heaven, it plainly appears that not by possibility only, but actually–as we say–is the grace of adoption offered to us by Christ.” (John Calvin, Commentary on the Gospel of John, on John 1:12)
Quotes from the Reflection for Trinity Presbyterian Church.