Whereas ye know not what shall be on the morrow; whether ye yourselves shall continue till then, or what else shall then be, or not be. In vain do ye boast of whole years, when ye cannot command the events of one day. For what is your life? This question implies contempt, as 1 Samuel 25:10 Psalms 144:3,4. It is even a vapour; like a vapour, frail, uncertain, and of short continuance; and then how vain are those counsels and purposes that are built upon no more sure a foundation than your own lives.
Related Commentaries of James 4:14
James 4:14
14 Whereas ye know not what shall be on the morrow. For what is your life? It is even a vapour, that appeareth for a little time, and then vanisheth away.