James describes a hypothetical situation where someone objects to his teaching. James seeks to correct his audience's understanding of faith and works. (See: [[rc://en/ta/man/translate/figs-hypo]])
James is describing how someone may argue against his teaching and how he would respond. This can be restated to remove the abstract nouns "faith" and "works." AT: "'It is acceptable that you believe God and that I do what God commands.' Prove to me that you can believe God and not do what he commands, and I will prove to you that I believe God by doing what he commands" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])