The Spirit Bringing Far Greater Liberty of Service in New Covenant Times – Robert Shaw WCF XX

3. Christians enjoy fuller communications of the free Spirit of God than were ordinarily granted to believers under the law. The Spirit had, no doubt, been dispensed to the Church under the Old Testament; but the more extensive and copious effusion of the Spirit was reserved to New Testament times. Hence the Spirit is said not to have been given before that Jesus was glorified.–John vii. 39. The plentiful effusion of the Spirit was frequently foretold as the great privilege of gospel times. Isa. xliv. 3; Joel ii. 28, 29. Accordingly, upon the ascension of Christ, and the commencement of the Christian dispensation, the extraordinary and miraculous gifts of the Spirit were communicated, not only to the apostles, but often to common believers; and the ordinary gifts and gracious influences of the Spirit are still conferred in richer abundance than under the former dispensation. Hence the Apostle Paul represents it as an eminent part of the glory of the New Testament dispensation, that it is “the ministration of the Spirit.”–2 Cor. iii. 8.

From Reformed.org

The Christian Serves God Freely Without Fear – Robert Shaw WCF Chapter XX

1 John 4:18 – There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love.

2 Corinthians 3:17 – Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty.

Luke 1:74–75 – That he would grant unto us, that we being delivered out of the hand of our enemies Might serve him without fear, In holiness and righteousness before him, All the days of our life.

2 Corinthians 5:14–15 – For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead: And that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again.

11. Believers have freedom of spirit in the service of God. The obedience which wicked men pay to God is like that of slaves to a tyrant, whom they hate, and whose only motive to obedience is a fear of punishment. But believers are delivered from a slavish fear of wrath, and serve God from a generous principle of love, and with a willing mind. “Where the Spirit of the Lord is, there is liberty.”–2 Cor. iii. 17. See also Luke i. 74, 76; 2 Cor. v. 14; l John iv. 18.

From reformed.org