Letham, the Pactum Salutis, and ESS

Martin writes of "the will of the Father" and "the will of the Son." However, the Trinity is simple, with one indivisible will. (Robert Letham, Systematic Theology, p. 435)

There are two kinds of covenant in the Bible. The first kind is a one-sided imposition. Applied to the relations of the Father and the Son (leaving the Holy Spirit aside!), this would mean subordination. The other covenant type is a quid pro quo, a voluntary contract between two or more persons. This requires the parties to be autonomous agents. Applied to the Trinity, this type of covenant implies that each person has his own will, entailing something approaching Tritheism. Both of these elements are present in the pactum salutis. In short, in constructions like this its compatibility with classic Trinitarian theology is questionable. It veers towards subordinationism or tritheism. (pp. 435-6)

The focus of the pactum salutis on contractual agreement misses the heart of what God's covenant is about. (p. 437)

In his Systematic Theology, Robert Letham rejects the concept of the pactum salutis. Letham does not reject the idea that God planned salvation from eternity. But what he rejects is that there is any covenant involved betweeen the Father and the Son. According to Letham, holding to the covenant concept implies either subordination or tritheism - the former if one party unilaterally sets the covenant, and the latter if both parties are involved in the covenant. Key to this assertion is the idea that the parties to the covenant need to act to ratify the covenant, but can a God who is simple and with one will acts separably in the persons?

It is evident that this is the precise problem facing Reformed theologians who claim to both hold to the Pactum and yet reject ESS (Eternal submission of the Son). Letham sees clearly that the two are in conflict. If one holds to a simple God with a single will without differentiation, there is no way to hold to the Pactum. Yet the Pactum is clearly taught in Scripture in places such as Psalms 110. Using the theory that God has a single will without differentiation (a theological concept) to reject what is clearly taught in Scripture is allowing external philosophical concepts to influence how one interprets the text of Scripture, or in other words eisegesis. Letham is consistent in his rejection of the Pactum, albeit consistently wrong. But those who continue to hold to a single will without differentiation yet reject ESS are more biblical, yet inconsistent. For if there is a single will, how can the Father covenants with the Son? The Father cannot covenant with the Son since the one will cannot covenant with itself, for a covenant requires at least two wills in the two parties!

If we believe God is truly the God of Truth, then we must be consistent. That is why we must reject the philosophical notion of a single divine will without differentiation. Just as we cannot claim that God being one means a rejection of the doctrine of the Trinity, so likewise we cannot claim that God being one and simple means a rejection of ESS. It is up to the theologian to formulate a philosophy and theology that can incorporate all biblical truths, not use one to embrace some and reject others.