أَشَابَ الصَّغِيرَ وَأَفْنَى الْكَبِيرَ كَرُّ الْغَدَاةِ وَمَرُّ الْعَشِيِّ
The recurring morning and passing evening made the young grey and brought the old to an end.
The expressions for the return of morning and the passing of evening are treated as though they actively grey hair and end lives. Their association with the passage of time makes the predicational transfer comprehensible.
The rhetorical force lies in personifying the relentless process of time. The point is to recover the relation of cause or temporal setting, not to assign physical agency to periods of day.