Meditations 6.15

Some things are hurrying into existence, and others are hurrying out of it; and of that which is coming into existence part is already extinguished. Motions and changes are continually renewing the world, just as the uninterrupted course of time is always renewing the infinite duration of ages. In this flowing stream then, on which there is no abiding, what is there of the things which hurry by on which a man would set a high price? It would be just as if a man should fall in love with one of the sparrows which fly by, but it has already passed out of sight. Something of this kind is the very life of every man, like the exhalation of the blood and the respiration of the air. For such as it is to have once drawn in the air and to have given it back, which we do every moment, just the same is it with the whole respiratory power, which thou didst receive at thy birth yesterday and the day before, to give it back to the element from which thou didst first draw it.

Marcus Aurelius, Meditations 6.15, translated by George Long

Some things are hastening to be, others to be no more, while of those that haste into being some part is already extinct. Fluxes and changes perpetually renew the world, just as the unbroken march of time makes ever new the infinity of ages. In this river of change, which of the things which swirl past him, whereon no firm foothold is possible, should a man prize so highly? As well fall in love with a sparrow that flits past and in a moment is gone from our eyes. In fact a man's life itself is but as an exhalation from blood and an inhalation from the air. For just as it is to draw in the air once into our lungs and give it back again, as we do every moment, so is it to give back thither, whence thou didst draw it first, thy faculty of breathing which thou didst receive at thy birth yesterday or the day before.

Marcus Aurelius, Meditations 6.15, translated by C. R. Haines