This is contrast to godly, heavenly and spiritual wisdom from God. The wisdom that is from above is first pure, then peaceable, gentle, and easy to be intreated, full of mercy and good fruits, without partiality, and without hypocrisy (James 3:17). Such wisdom produces the fruit of righteousness, which comes from a heart of peace for "the fruit of righteousness is sown in peace of them that make peace" (James 3:18).
He blinds people with pride, making them think they are good for what they do in serving themselves, because they "deserve" it. He incites hate between people in conflict by deceiving those on both sides who are under his control to think they "deserve" what they are fighting for.