Jesus in the decretal system that funds Calvinism becomes the organon (Ὄργανον) or instrument of salvation, which is the fatal flaw of the decretal system in a God-world relation. Jesus meets the condition set by the absolute decree (decretum absolutum) for the elect, thus becoming the means by which humanity is reconciled to God. The problem with this scheme is it rips asunder the work of God from the person of God, thus subordinating Jesus to something like a demiurge or go-between or in fact, payment, meeting the conditions of the covenant of works as God’s act of grace for the elect.

Translation: the Son become flesh in Jesus merely becomes an instrument of the Father to procure salvation for the elect. I.e., Jesus’ divinity in this scheme is not required for salvation to obtain. The penalty paid is what is required, and Jesus meets that condition. This is what a purely forensic or juridical understanding of the atonement produces.