Romans 10:10

Romans 10:8-10 
But what does it say? “The word is near you, in your mouth and in your heart”—that is, the word of faith which we are preaching, that if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you will be saved; for with the heart a person believes, resulting in righteousness, and with the mouth he confesses, resulting in salvation. 

Steven Hitchcock: “When Paul says, ‘With the heart a person believes’ he is not speaking of a heart that has already been regenerated. Paul is speaking about the same heart that belongs to a sinner who is estranged from God.” (Recanting Calvinism, p.132)

Hitchcock adds: “Notice that Paul says that when this sinful heart believes it results in righteousness. The Calvinist would have to say that the righteousness here spoken of is the righteousness of Justification, because he thinks that Regeneration has already taken place. But this verse says that ‘salvation’ has resulted from such faith. Can a Calvinist justly maintain that Regeneration is not salvation?” (Recanting Calvinism, p.132)

For a Calvinist, one who is Pre-regenerated with an Irresistible Grace, is also in Christ (as Calvinists admit), and being in Christ, requires that one is righteous (compare with Romans 8:1), and therefore, you cannot also maintain that faith results in righteousness. Calvinism would thus have an unbelieving, Pre-regenerated elect person in Christ, be righteous (on account of being preemptively in Christ), then believing, resulting in righteousness. So for the Calvinist, there is a paradox.

Romans 10:14-15: How then will they call on Him in whom they have not believed? How will they believe in Him whom they have not heard? And how will they hear without a preacher? How will they preach unless they are sent?

For a Calvinist, the answer for how then is preemptive regeneration, and yet Paul makes no such reference to Pre-regeneration as the means to believe. Paul simply speaks of a preacher with the Word of God as being the vital necessity. Although it’s an argument from silence to disprove Calvinism based upon what is unstated, one would also have to admit that if Paul was a Calvinist, he missed an easy opportunity to discuss Pre-regeneration, as the answer to his own question.

Steven Hitchcock: “Paul gives no indication here that a previous work of God, namely Regeneration, is required in order for the one who has not believed to believe. In fact, in Romans 10:17 he says, ‘so faith comes from hearing, and hearing by the word of Christ.’” (Recanting Calvinism, p.133)

If faith comes by Pre-regeneration, Irresistible Grace or Unconditional Election, Paul certainly missed a golden opportunity to say so, in answer to his own question.