Consider in what condition both in body and soul a man should be when he is overtaken by death; and consider the shortness of life, the boundless abyss of time past and future, the feebleness of all matter.
AI put this 1862 translation into today's English. Only the wording changed: each rewrite was checked against the original to keep its exact meaning.
Original translation
“No longer talk at all about the kind of man that a good man ought to be, but be such.”
Translated by George Long, 1862
“Time is like a river made up of the events which happen, and a violent stream; for as soon as a thing has been seen, it is carried away, and another comes in its place, and this will be carried away too.”
― Marcus AureliusMeditations (Book XII, Section 7)