Life means human existence. To linger is to remain. A moment is less than one hour (half a traditional shichen). Old friends are long‑standing kin and companions. To grieve means to feel sorrow. Though the lecher clings to life for a brief span, all who once knew him are filled with sadness.
He looks far back upon former days, too pained to turn and recall.
To look far back is to reminisce. The former days refer to earlier days. Being too pained means being unable to bear it. To turn and recall is to look back. As he thinks of the joy he once knew before his ruin, he cannot bear to revisit those memories.
Such a wretched end calls for no sighs of pity.
“Such” means “this kind of”. A wretched end means one’s final lot. “Calls for no” means there is no need for. This miserable fate is the lecher’s just due; no compassion or lament is owed him.
As for skilled craftsmen, they too ought to abide by established rules.
Craftsmen are artisans and tradespeople, such as various industrial and technical workers. “Skilled” means “accomplished”. “Established rules” refer to precepts and standards. One who has learned a trade ought to uphold the rules handed down by his master and must never yield to licentiousness.
Some disregard their master’s teachings, arranging secret trysts for illicit lodging, and spurn their friends’ warnings, craving clandestine pleasure beneath the moon.
Master’s teachings are the precepts against licentiousness given by one’s trade instructor. To disregard is to disobey. Arranging secret trysts means making clandestine plans to meet another’s woman at an inn for illicit congress. He pays no heed to friends who warn him against lechery, yet pursues secret moonlight rendezvous with other women.
No matter how fair and delicate the maiden, none escape the iron net. Regardless of her blossom‑like face and moon‑bright beauty, the gilded hook lies in wait.