What does James 4:13 mean?
In the previous verse, James warned about arrogantly judging our neighbors for their sinfulness. Now he begins a section about the arrogance of imagining that we have total control over the events of our own lives. Over the next few verses, he will point out that true humility means recognizing our limitations. We really don't know everything about the future. Even our best planning is still subject to God's will.This verse sets up this point with a generic business plan. The problem here is not in making the plan—James doesn't go on to say that planning is sinful, or foolish. The problem James is relating, by using this example, is an attitude of self-reliance. "Tomorrow, I will do this or that." Verse 16 shows the attitude James intends behind the words of this verse. Making such a statement, out of confidence in one's own ability, and without humility, is unwise.
The context of the prior passage is important. James has been discussing the problem of following the thought process of the world, instead of the wisdom of God. Here, James imagines a businessman declaring how he will make more money, how he will get what he wants out of life. In context, this is meant to mean one who is planning according to the pattern of the world. This man is making plans and vowing to keep them in his own power and by the force of his own will.
That's not the life of dependence God calls His children to walk in.