Decided its best to do bigger blocks of text so there is room for more questions.
So lets wrap up James 4
Brothers, do not slander one another. Anyone who speaks against his brother or judges him speaks against the law and judges it. And if you judge the law, you are not a practitioner of the law, but a judge of it. There is only one Lawgiver and Judge, the One who is able to save and destroy. But who are you to judge your neighbor?
Come now, you who say, “Today or tomorrow we will go to this or that city, spend a year there, carry on business, and make a profit.” You do not even know what will happen tomorrow! What is your life? You are a mist that appears for a little while and then vanishes.
Instead, you ought to say, “If the Lord is willing, we will live and do this or that.” As it is, you boast in your proud intentions. All such boasting is evil. Anyone, then, who knows the right thing to do, yet fails to do it, is guilty of sin.