Because we have been saved

Michael Kruger explains here several reasons why the book Luther described as an “an epistle of straw” is important to Christians. The second reason:

.... James reminds us that Christians should also view the Law of God positively. Compared to Paul’s insistence that the law is a “curse” that “imprisons” us (Gal 3:13, 22), James’ approach to the law is shockingly positive. He refers to the law as the “law of liberty,” or as the NIV puts it, “the perfect law that gives freedom” (Jas 1:25).

Do Paul and James contradict each other? Not at all. Paul is looking at the law from the perspective of justification–can I be saved by law-keeping? If you try this, says Paul, the law is only a curse. James is looking at the law through the lens of sanctification. From this perspective the law is a blessing. It is the way of righteousness. We can say with the Psalmist, “Oh how I love your law!” (Ps 119:97).

Paul reminds us that the law cannot save. James reminds us that we follow the law because we are saved. Both aspects are critical if we are to rightly understand justification and sanctification. .... [more]

Why We Need the Book of James in the New Testament Canon | Canon Fodder