For what is your life? It is even a vapor that appears for a little time and then vanishes away.
God has wisely left us in the dark concerning future events, and even concerning the duration of life itself.
We know not what shall be on the morrow. We may know what we intend to do and to be, but a thousand things may happen to prevent us. We are not sure of life itself, since it is but as a vapour, something in appearance, but nothing solid nor certain, easily scattered and gone.
We can fix the hour and minute of the sun’s rising and setting tomorrow, but we cannot fix the certain time of a vapour’s being scattered. Such is our life: it appears but for a little time, and then vanisheth away.
It vanisheth as to this world, but there is a life that will continue in the other world. And, since this life is so uncertain, it concerns us all to prepare and lay up in store for that which is to come.”
—from Matthew Henry’s Commentary on the Whole Bible. Available at Blue Letter Bible.