Sola fide, or what is faith?

In short, if you mentally agree that Jesus died for your sins, then nothing else is required for your salvation— you are on your way to heaven. The problem here is a deficient definition of faith (and for that matter of salvation). Advocates of free—grace salvation have correctly recognized the primacy of God’s grace and the necessity of holding certain doctrines as “true” or “real,” but by effectively reducing faith to intellectual assent, they have introduced a dangerous error.

Nobody, even in the free—grace movement, wants to claim that the demons in Mark’s Gospel—who know Jesus’s divine origins and who utter, “I know who you are, the Holy One of God!” (Mark 1:24) and “You are the Son of God” (3:11)—are in actuality saved because of their true knowledge of Jesus. Free—gracers are quick to disavow such a conclusion. All would agree with the Letter of James, which affirms that such “facts” are not enough: “You believe that God is one. You do well. Even the demons believe and shudder” (James 2:19). Nonetheless, problematically, at least some in the free—grace movement want to make salvation depend on nothing but a slight variation of the Son-of-God fact, an affirmation that Jesus died for my sins.—Matthew W. Bates, Salvation by Allegiance Alone, 25