CONSIDER the flight of time!1
Verily, man is bound to lose himself
unless he be of those2 who attain to faith, and do good works, and enjoin upon one another the keeping to truth, and enjoin upon one another patience in adversity.
The term 'asr denotes "time" that is measurable, consisting of a succession of periods (in distinction from dahr, which signifies "unlimited time", without beginning or end: i.e., "time absolute"). Hence, 'asr bears the connotation of the passing or the flight of time - time which can never be recaptured.
Lit., "man is indeed in [a state of] loss, except those....", etc.