In his second disputation with Balthasar Hubmair, in 1523, Huldrych Zwingli well articulated the formal principle of the Reformation: “For in all controversies concerning faith and religion, the divine Scripture alone ought to be our measure and rule rather than oral tradition.” That Zwingli articulated this principle in the context of a debate with one of the leading first-generation Anabaptists suggests that those who are argue that Zwingli did not become an Anabaptist (which he was tempted to do) because he did not really believe the sola Scriptura principle (or because he was afraid to run afoul of the civil authorities) have misunderstood Zwingli. It was because of his reading of Scripture that Zwingli rejected the Anabaptist eschatology and their understanding of redemptive history. Just as Barnabas, Irenaeus, and Justin Martyr had rejected the Gnostic and Marcionite dichotomy between Moses and Christ in favor of a unified covenant of salvation, which the Reformed would later call a covenant of grace, so too Zwingli, Oecolampadius, and Bullinger would argue that the Old and New Testaments are fundamentally unified by a single covenant of grace. They recognized diversity in the administration of the covenant of grace under Adam, Noah, Abraham, Moses, David, and the Prophets. Zwingli and other of the early Reformed theologians recognized that there was a temporary quality to the Mosaic administration of the covenant of grace that distinguished it from the other administrations. They recognized a strong continuity between the Abrahamic administration of the covenant of grace and the new covenant.
In 1524, in his Exposition of the Articles he explained the relationship between covenant and baptism in these points:
- Baptism is being enrolled by an “oath of allegiance” (sacramentum) into the church visible,
an initiation into the people of God.
- If there is one people of God, with one faith, in one Savior, then it follows that the signs and seals of that salvation, Savior and faith, have not changed radically.
- Thus, he appealed to Colossians 2:11–12, where Paul linked circumcision and baptism, as evidence that Christian parents ought also to administer the sign of the covenant to their children.
- He agreed with Luther that the Sacraments strengthen faith, but he was clear to say that they do not give it. This is the work of the Spirit through the Word.
- Against the Anabaptists (i.e., Schwenkfelders) he argued that they added to Scripture by denying paedobaptism. NT is silent, therefore the command to administer the sign of the covenant continues to apply today.
- By forbidding it, they were adding to Scripture and doing exactly what Jesus said not to do: forbidding the children to come to him!
- If we deny that children should be baptized, then we must deny that women should come to the table, because there is no positive evidence that they were communicated in NT.
- If John’s baptism is substantially the same as Christ’s, then there is no categorical necessity of being discipled before baptism since John’s disciples had not even heard of Christ before they were baptized. John’s baptism was prospective and Christ’s retrospective.
- Certainly children were baptized in the OT. All Israel, children and adults were baptized with Moses in the Red Sea (1 Cor. 10).
- Children of believers are born with original sin, but not original guilt and are therefore eligible for baptism.
- How can the children of NT believers be worse off than the children of the Jews who received the sign of the covenant, since this is a better covenant?
- The sign of initiation, in both covenants, always entailed a pledge to renew it with one’s children, hence the sign.
The Reformed did not necessarily continue every single line of argument he made in 1524 (e.g., his distinction between original sin and original guilt) but the continuity between the earliest Reformed understanding of the covenant of grace (and infant baptism) and the later, more mature expressions (e.g., Bullinger’s 1534 treatise on the covenant of grace), even Calvin’s in the 1540s–60s and those of the Heidelberg theologians in 1560s–70s) are unmistakable.
In Zwingli’s mind and in the understanding of the later Reformed writers, the fundamental unity of the covenant of grace between Abraham and the new covenant was not a mere convention, i.e., it was not arbitrary. They saw it in the text of Scripture. They were driven to it by Scripture itself. Their covenant theology was an accounting of Scripture. It was an attempt to account for turning points in the history of redemption, where the covenant plays a key role, whether in Genesis chapter 6 or chapters 12, 15, and 17 and Jeremiah 33 or in the institution of the Lord’s Supper (e.g., Luke 22) or in Paul’s account of redemptive history in 2 Corinthians 3, Galatians 3–4, or in Hebrews chapters 7–10. The early Reformed were not, as is sometimes alleged, merely looking for an ex post facto justification of medieval practice but accounting for Scripture itself. In Zwingli’s mind, infant baptism was the product of sola scriptura.