The NIVAC series is my go to for sermon prep. David Nystrom, just like the letter of James, challenges the believer in many ways. He does a fantastic job of demonstrating numerous ways in which a believer walks a double-minded life. He uses a rich variety of sources, which the reader can access well in the footnotes. This commentary was fantastic. I would recommend it for anything from devotional reading, to Sunday School prep, to sermon prep, to scholarly paper prep.
You will see reviews stating that he gives too much opinion. This is what I greatly appreciate! He takes the time to bridge the text into the uncomfortable and idolatrous corners of our heart that the initial letter of James "to the 12 tribes scattered" was meant to address. Too often we let the epistles of Scripture sit comfortably 2000 years ago, without seeing just how much of what we normalize is the same sin that God was addressing. I applaud the way that Dr Nystrom wrote this commentary.