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”; 14 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. 15 Instead you ought to say, “If the Lord wills, we shall live and do this or that.” 16 But now you boast in your arrogance. All such boasting is evil. James 4:13-16
We may take tomorrow for granted, thinking of it as a mark on the rim of time’s wheel, coming on inevitably as the circling years proceed. But in the Bible the years do not circle. They go in a straight line from eternity to eternity, and on that line we receive another day neither by natural necessity, not by mechanical law, nor by right, nor by courtesy of nature, but only by the covenanted mercies of God.
J.A. Motyer, The Message of James