Calvin’s service for the Lord’s Day is a liturgy of the Word in at least three senses. First, the central act of the liturgy is the sermon, the faithful expounding of God’s Word for the edification of His church. The sermon is preceded by the invocation of God’s name, the confession of sins with absolution, the singing of a psalm, and the minister’s prayer for the help of the Holy Spirit in preaching—all of which prepare for profitable hearing of the Word. The sermon is followed by intercessory prayer, incorporating an expanded paraphrase of the Lord’s Prayer; repetition of the Apostles’ Creed; administration of the sacraments; and finally, a benediction. All are acts of faith in response to God’s Word.
Second, the service includes only those elements that have a warrant in the Word of God; later generations called this directive the “regulative principle of worship.” No scope is given to the mind or imagination of man. Calvin said that following one’s own notions, other men’s inventions, or man-made traditions in worship is an act of apostasy and idolatry, a falling away from the truth of God’s Word, and the worship of something false in the place of what God has instituted. Commenting on Christ’s word to the Samaritan woman in John 4:22, “Ye worship ye know not what,” Calvin observes, “However much in their obstinacy those who worship God from their own notions or men’s traditions flatter and praise themselves, this one Word thundering from heaven overthrows every divine and holy thing they think they possess: Ye worship that which ye know not.”4
Third, the content of each part of the liturgy is drawn from Scripture, from Psalm 124:8, used as an invocation at the commencement of the service, to the Aaronic benediction (Num. 6:24–26) at the close. The prayers abound with Scripture citations and allusions, each paragraph invoking some particular promise, precept, or precedent, followed by the application of it to the needs of the congregation or the wider church. When Scripture is not being read, preached, or appropriated in prayer, it is being sung as praise to God in the form of a metrical version of a psalm. First to last, Calvin’s liturgy is an encounter with the truth of Holy Scripture.
4 John Calvin, “The Gospel according to St. John, 1–10,” Calvin’s New Testament Commentaries, trans. T. H. L. Parker (Grand Rapids: Eerdmans, 1959), 99.
 Ray Lanning, “Chapter 17: Foundations of Reformed Worship” In , in Living for God’s Glory: An Introduction to Calvinism (Lake Mary, FL: Reformation Trust Publishing, 2008), 232-33.