Before we start, I do want to make the statement that, though there are several ideas over what does and does not constitute Calvinism, for the sake of maintaining the speakers original intent, we will treat every belief as a true belief of Calvinism and then attempt to show that it is also a critical aspect of the gospel, thus proving that whatever is Calvinism is also the gospel, and therefore Calvinism is the gospel.
Now, to begin our argument from Spurgeon’s famous quote that Calvinism really is the gospel, we will look at what he first gives as the evidence of this:
Calvinism is the gospel, and nothing else. I do not believe we can preach the gospel if we do not preach justification by faith without works . . .
So, Spurgeon’s initial evidence that Calvinism is the gospel is because it preaches justification by faith without works. This belief, however, is not just Calvinism. The belief that justification is by faith apart from works is the backbone of all protestant thought. Therefore, showing that it is most crucial to the gospel should not be too controversial unless we have some ardent Catholics peering in on us.
To show that preaching justification by faith apart from works is core to preaching the gospel, all wwe have to do is look at a few of the most important evangelistic verses in the Scriptures. Ephesians 2.8-9 goes right for it saying, “For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast.” Follow this with Romans 3.28, “For we hold that one is justified by faith apart from works of the law,” and it is pretty much a closed case that justification by faith is as fundamental to the gospel as anything possibly could be. It is good news because it means we are not having to be in the business of saving ourselves, this has already been done for us. Nothing could be better news than knowing that your debt of sin is taking care of by someone else and all you must do is believe; that though you deserved death, God freely gave his son to die as a sacrifice for us that we may be reconciled with him.
Therefore, one evidence in and the claim that Calvinism is the gospel appears to doing pretty well. Of course, the hard part is yet to come.