What Does Same in Substance but Different in Administration Mean?
Reformed covenant theology is known for seeing greater continuity between the Abrahamic, Mosaic, and new covenants than that of older theological systems, such as Socinianism, Anabaptism, and English Antinomianism, as well as newer ones like Dispensationalism. Moreover, Reformed covenant theology captures its distinctive view with the formula: same in substance but different in administration. The three covenants are the same in terms of their substance, yet they differ regarding their administration.
The meaning of this formula, however, is sometimes misunderstood by defining it in terms of its implication. What do I mean by this? It has been said that sameness in substance simply means that there has only been way of salvation throughout the history of redemption. For example, Mark Karlberg says it pertains to “eternal salvation,” and that “the unifying substance of the covenant of grace was a way of speaking of the exclusive way of salvation through grace, of justification by faith, not human works.[1] Similarly, Harrison Perkins argues that the Reformed view is that the covenant of grace is one substance “because Christ and his saving benefits are distributed to believers in every age, whether Old or New Testament.”[2] In other words, “the one covenant of grace is unified in substance because, although the historical covenants function diversly in redemptive history, there has always been only one way of salvation since the fall.”[3]
One way of salvation, however, is an implication or entailment of same in substance, not its meaning. The puritan John Ball, for example, notes that if the covenants are the same in substance “then it must necessarily follow, That there is but one Church of the Elect, the same Communion of Saints, one Faith, one Salvation, and one way of obtaining the same, viz. by Faith in Christ.”[4] That which must necessarily follow is an implication and should not be confused with its meaning.
What then does same in substance but different in administration mean? In accordance with Robert Rollock’s basic definition of a covenant being a promise under a condition, the substance of a covenant primarily consists of its promise(s) and condition(s).[5] Thus, John Ball says the “essence of the Covenant properly consisteth in the Promise and stipulation.”[6] The administration of a covenant is the manner or means by which the substance (promises and conditions) is dispensed, applied or communicated. The Promised Land is often used to illustrate the difference in administration between the Mosaic and new covenants. The promise, which constitutes part of the substance, is the same in both covenants, namely heaven. The administration of it is different. God dispenses the promise by a type or figure—the land of Canaan—in the Mosaic covenant and he dispenses the same promise by the antitype—heaven itself—in the new covenant. Same in substance (promise of heaven), different in administration (type and antitype).
Since the substance of a covenant are its promises and conditions, covenants that are the same in substance have the same promises and conditions. Hence, Edward Fisher, the author of the Marrow of Modern Divinity, says that a “certain rule” which applies to all covenants is that “if the subject matter, the fruit and the conditions, be the same, then is the covenant the same.”[7] This is why same in substance implies one way of salvation. Nonetheless, it is possible to reject the Reformed formula and still hold to one way of salvation. For example, it is possible to believe that the Mosaic covenant is a temporal works covenant and thus different in substance from the new covenant, while at the same time believe that the saints under the Mosaic covenant were saved in the same way as the saints in the new covenant. This is in fact what advocates of a 17th century view on the Mosaic covenant called the Subservient Covenant believed. One does not need to hold to the Reformed formula to hold to one way of salvation. But if one does hold to it, then he should also affirm one way of salvation because it is a necessary implication.
Understanding the proper meaning of the Reformed formula helps us to see that the modern notion of what is now called “administrative republication” is incoherent. Administrative republication says that the Mosaic covenant is in substance grace but works in administration. A covenant, however, that is in substance grace must be administered graciously. To introduce a different condition (e.g. works as opposed to grace) or a different promise (temporal life as opposed to eternal life) in the Mosaic covenant, which must be on the typological level because it is an Old Testament covenant, is to change the substance of the covenant. If the terms of the covenant are changed, the substance is changed, and not merely its administration, because the terms are its substance. This is why it doesn’t make sense to say that a covenant with respect to its substance has one kind of condition and a contradictory condition with respect to its administration. The administration can only apply the substance and thus the condition that pertains to its substance and not some other condition that does not pertain to its substance.
The mainstream view of Reformed covenant theology teaches that the Abrahamic and Mosaic covenants are the same in substance with the new covenant, only differing in terms of administration. This means that the covenants all have the same promises and conditions, which implies that there is and only has been one way of salvation. This also means that “the demand of obedience in the Mosaic covenant is principially identical with the same demand in the new covenant of the gospel economy.”[8] Although this view has been called “monocovenantalism,” it is simply classic, confessional Reformed orthodoxy. For a more in depth look at this issue, see my article “Same but Different: The Meaning and (Mis)Use of a Reformed Formula” in the 2025 edition of the Mid-America Journal of Theology.
[1] Mark Karlberg, “Reformed Interpretation of the Mosaic Covenant,” Westminster Theological Journal 43 (1981): 16; Mark W. Karlberg, “Legitimate Discontinuities Between The Testaments,” Journal of The Evangelical Theological Society 28/1 (March), 11.
[2] Harrison Perkins, Reformed Covenant Theology: A Systematic Introduction (Bellingham, WA: Lexham Academic, 2024), 188.
[3] Perkins, Reformed Covenant Theology, 188.
[4] John Ball, A Treatise of the Covenant of Grace (London, 1645), 30.
[5] Robert Rollock, A Treatise of God’s Effectual Calling (London, 1603), 6.
[6] Ball, Covenant of Grace, 4.
[7] E.F. The Marrow of Modern Divinity (London, 1645), 65. Fisher cites Ursinus in the margin.
[8] John Murray, Principles of Conduct (Grand Rapids, MI: Eerdmans), 199.
