Come now, you who say, “Today or tomorrow we will go to such and such a city, spend a year there, buy and sell, and make a profit”; whereas you do not know what will happen tomorrow. For what is your life? It is even a vapor that appears for a little time and then vanishes away. Instead you ought to say, “If the Lord wills, we shall live and do this or that.” (James 4:13-15).
This passage is not a diatribe against planning, nor is it strictly a caution against materialism. There are certainly dangers in overplanning, it is true, but virtually nothing is accomplished without planning; and materialism is sin, but we all use and need material things. Rather, it is talking about living as though your tomorrows are guaranteed. According to James, they most definitely are not.
This truth is very hard for some to accept because it leads right into the deep waters of God's sovereign will. These waters are deep because we only know that will as God unfolds it. This rankles us, even though we have God's revealed will in the scriptures, because we think we need to know what is going to happen so that we can better serve God and His revealed will.
The truth is we don't like the unexpected at all. Even though we know God owns the future and will be with us in it, there is an element of uncertainty that we would just as soon do without. We'd rather that our faith become sight on this side of the grave, not so much because it would better help us serve God as that it would take some of the scary adventure out of faithful living. If this is our thinking, James's words don't come as good news. For if James is right, the faithful Christian can have but one conclusion—God knows what is best. It is our job to fit into His plans—which are often revealed to us as we go along.
When James says “Why, you do not even know what will happen tomorrow,” He is only emphasizing that someone who does not know what will happen tomorrow certainly won't be able to presume on something a year from now. And this is especially true if someone's life is but a “mist that appears for a little while and then vanishes.”
“If it is the Lord's will, we will live and do this or that” is not to be taken as a lucky charm. We are not to use it as though we were knocking on wood in order to protect us from a “sneaky” God who might be about to pull a surprise on us in case we aren't humble. Rather, the expression should represent our genuine conviction that God is sovereign in everything. If He permits us to move to another city and engage in successful business for a year, that is all to His glory. He has permitted it; we are His servants; He gets the praise.
“But now you boast in your arrogance. All such boasting is evil. Therefore, to him who knows to do good and does not do it, to him it is sin.” (James 4:16-17).
By contrast, any other attitude is boastful and arrogant. The people to whom James was writing were quite content to live as though God would automatically put His rubber stamp of approval on their activities without their having to acknowledge His authority over all that comes to pass. That God's will has been of little or no concern is evidenced by their amazing certainty about the future. Since our future has not been revealed to us by God, to presume on it is sin.
Verse 17 summarizes, then, what James has been saying; Knowing good and doing good are always practical matters of both obeying God and avoiding evil. You can't have one without the other. Mere avoidance of evil doesn't fulfill the highest aspects of God's calling for us to be His people. Jesus called the Pharisees a “brood of vipers” and capable of making people “twice as much sons of hell” because they were more intent on avoiding uncleanness than in helping the sinners in their midst.
We think we have tomorrow because we are used to having tomorrow come, not realizing that everyday is a gift from God. David prayed: “Teach us to number our days aright, that we may gain a heart of wisdom” (Psalms 90:12). knowledge of our own mortality is a first step in coming to depend on God—for everything.