Ps 102:15

“Our life on earth, brothers, is such that our existence is very transitory. We play, as it were, a game on earth: we do not exist, and we are born, and being born we are dissolved. We are like a fleeting dream, an apparition without substance, the flight of a bird that passes, a ship that leaves no trace on the sea. We are dust, a vapor, the morning dew, a flower growing but a moment and withering in a moment. "[A] man's days are as grass: as the flower of the field, so shall he flourish." Beautifully has blessed David meditated on our weakness. Again he says, "Declare to me how few are my days." He defines the days of humankind as the measure of a handbreadth. What would you say to Jeremiah, who, complaining of his birth, even blames his mother, and that, for the failings of others? "I have seen everything," says Ecclesiastes. I have reviewed in my mind all human things, wealth, luxury, power, glory that is not stable, wisdom that eludes us more often that it is mastered.”

“Concerning the resurrection more will be said later; but now let us return to our immediate subject. We have shown that even holy people have, without any consideration for their merits, suffered many difficult things in this world, together with toil and misery. So David, in self-reflection, says, "Remember, Lord, that we are dust; as for [a] man, his days are but as grass"; and in another place, "[A] man is like a breath, his days pass away as a shadow." For what is more wretched than we, who are sent into this life as it were plundered and naked, with frail bodies, deceitful hearts, weak minds, anxious in regard to cares, slothful as to labor, prone to pleasures.”

“"Man, his days are but as grass" [Psalm 103:15]. Let man consider what he is; let not man be proud. "His days are but as grass." Why is the grass proud, that is now flourishing, and in a very short space dried up? Why is the grass proud that flourishes only for a brief season, until the sun be hot? It is then good for us that His mercy be upon us, and from grass make gold. "For he flourishes as a flower of the field." The whole splendour of the human race; honour, powers, riches, pride, threats, is the flower of the grass. That house flourishes, and that family is great, that family flourishes; and how many flourish, and how many years do they live! Many years to you, are but a short season unto God. God does not count, as you do. Compared with the length and long life of ages, all the flower of any house is as the flower of the field. All the beauty of the year hardly lasts for the year. Whatever there flourishes, whatever there is warmed with heat, whatever there is beautiful, lasts not; nay, it cannot exist for one whole year. In how brief a season do flowers pass away, and these are the beauty of the herbs! This which is so very beautiful, this quickly falls. [Isaiah 40:6-8] Inasmuch then as He knows as a father our forming, that we are but grass, and can only flourish for a time; He sent unto us His Word, and His Word, which abides for evermore, He has made a brother unto the grass which abides not. Wonder not that you shall be a sharer of His Eternity; He became Himself first a sharer of your grass. Will He who assumed from you what was lowly, deny unto you what is exalted in respect of you?”