ANSWER: He is the Author of all the piety from Adam to the convert of today. But since Pentecost he has had a perfect chest of tools to work with, all the facts of Christ's earthly history and all the truths deduced therefrom by the inspired apostles. The result is that of a joyful assurance of sonship to God has taken the place of the servile feeling, characteristic of the saints under the Law. This transition is described in Gal. 4:7. The distinguishing peculiarity of the New Testament salvation is the attestation by the Holy Spirit of the believers adoption into the family of God and of the entire sanctification of those who claim their full heritage in Christ.
— from Steele's Answers pp. 37, 38.