I often get asked what distinguishes evangelical Calvinism from classical Calvinism; I think that one of the more instructive ways to illustrate this is to compare John Calvin with Karl Barth. It is the disparity between their respective hermeneutic that makes clear where the point of departure is at between EC and CC. For EC, following Barth at this juncture, the distinction is that we see things from a personalist rather than impersonalist perspective; in other words when we think about salvation we start immediately with Jesus Christ. Contrariwise CC’s, when they think about salvation start with decrees, and work mediately from there to Christ. This distinction is rife in the theologies of Calvin and Barth; as David Gibson notes, “…Calvin’s theology allows us to speak of Christ and the decree, but Barth’s theology to say that Christ is the decree….” Evangelical Calvinists think after Barth here, and depart from Calvin at this point. Gibson writes further as he comments on Calvin and Barth:
First, the patient work of a thick description will reveal why both of their respective doctrines of election may be described as christocentric. This establishes a similarity between both theologians. But secondly, precisely in this description of their christocentric doctrines of election, we will see a conceptual distinction emerging. Calvin’s doctrine of election is best described as christocentric in the soteriological sense: although in his theology election is connected to Christology in the realm of the inscrutable divine decree, the weight of his treatment falls on the nexus of ideas associated with the preaching of the gospel, the Spirit’s call and the response of faith in the Mediator. By having more to say about election’s connection to Christ in this temporal realm of faith and obedience, Calvin’s doctrine of election is an example of his soteriological christocentrism. By contrast, we will see that the opposite is true of Barth. The connection of election to Christology is not primarily to be found in something that God does (issue a decree) but rather, in the person of Jesus Christ, election describes who God is (turned toward us in his self determination). Barth’s understanding of Christology and election locates his christocentrism principially: it is the ‘ground and content’ of the doctrine of election, with this particular understanding itself having a determining influence on the divine being and intra-trinitarian life. Here Christology operates as a methodological rule which is more pervasive and radical than in the thinking of Calvin. Thirdly, the contrasts which emerge between a soteriological–principial christocentrism help to show that the difference between Calvin and Barth in the area of Christology and election is fundamentally explained by their contrasting understandings of how election is related to the doctrine of the Trinity.
Barth, and evangelical Calvinists after him, cannot conceive of God’s election but personally and ontically in Christ; thus the focus is personal, grounded in the personal and loving life of God as Triune. Calvin thinks from a voluntarist position where God’s will is given expression in an abstract decree. In other words, the decree is not something necessarily related to who God is; instead it arises from an abyss in God where there is no access (Deus absconditus)—God in this scheme arbitrarily chooses some and rejects others, and this based upon a remote and absolute decree. This is why Barth and Torrance charged this Calvinian and classically Reformed view with the idea that ‘there is a God behind the back of Jesus’. The God behind the back of Jesus is the abyss (inner-life of God) from whence the decrees are generated. But the God revealed (Deus revelatus) in Christ, for the evangelical Calvinist, after Barth, is the same God who antecedently co-exists eternally as Father, Son, and Holy Spirit (i.e. the ontological is the immanent Trinity). There is no distinct decree from Christ for the evangelical Calvinist; Christ is the ‘decree’ (to stick with that language).
The difference is personal rather than impersonal between the evangelical Calvinist and classical Calvinist.
 David Gibson, Reading the Decree: Exegesis, Election and Christology in Calvin and Barth (London/NY: T&T Clark, 2009), 30.
 Ibid., 30-1.