The book of Romans demonstrates that faith is an action term. For example, Paul commends the “faith” of these saints, which, says he, is “proclaimed throughout the whole world” (Rom. 1:8).
As he concludes the epistle, he again congratulates them: “For your obedience is come abroad unto all men” (Rom. 16:19). Faith and obedience are parallel here.
In fact, at the beginning and end of the book, the expression “obedience of faith” stands like a guardian sentinel, defining the character of biblical faith (Rom. 1:5; 16:26).
In Romans 10:16, those who refused to “obey the gospel” fulfilled Isaiah’s prediction that some would not “believe” the divine report.