James 4:14

‘What is your life? For you are a vapour, which appears for a little time, and then vanishes away.’

For what they should remember is what their lives are. They are not substantial. They are rather like a puff of smoke which appears for a short while and then disappears. They are like an early morning mist that soon clears away (Hosea 13:3). For life is brief, and in the midst of life we are in death. So in view of that it is in this light that they should measure how they ought to live, both with regard to judging others (in the face of the fact that we might ourselves face judgment at any time), and with regard to doing good (James 4:17). It is in this light that they should determine what they (or rather God) consider to be important. And if they truly recognise that their lives might disintegrate like a puff of smoke at any moment, they will undoubtedly put more consideration into looking at the things that are unseen, and building up treasure in Heaven (Matthew 6:17-18), for they will recognise that the things that are seen are temporal, and will soon pass away, while the things that are unseen are eternal (2 Corinthians 4:18).