FWP:
SETS == DIALOGUE; IDIOMS; IZAFAT; OPPOSITES
The verse of course is energized by the use of the proverb nādāñ kī dostī jī kā ziyāñ . The addressee is reminded (by himself or by a companion) that as a wise [dānā] person he ought not to cultivate 'a fool's friendship', and he'll suffer for it if he does.
Since dostī can refer to love as well as friendship, it's also part of the usual prudent advice that is always given to the lover by well-meaning friends. Thus the affinity of 'gain' in the first line and 'loss' in the second-- for a cost-benefit analysis is being urged. The beloved is reckless, unreliable, mischievous, silly, and radically nādāñ . Nobody with any brains would get involved with somebody like that! So the lover would be foolish to cultivate such 'a fool's friendship'-- the friendship of such a fool.
But of course, nādāñ kī dostī can mean not only friendship 'with' a fool, but also the friendship 'of' a fool. A dānā person ought not himself to act like a nādāñ one, by cultivating such an unsuitable friendship: on this reading, both dānā and nādāñ are made to apply to the lover. And what a perfect double description it is. The lover in some sense knows better, but does that ever stop him? As we all know, it doesn't even give him pause.
The children's comic below illustrates one such story about 'a fool's friendship': the man in blue has asked his friend the monkey to keep the flies away from him while he takes a nap. The well-meaning monkey sees a fly settle on his friend's nose, and prepares to take action.
Nazm:
It's a proverb, 'A fool's friendship: harm to the inner-self' [nādāñ kī dostī jī kā ziyāñ]. (27)
== Nazm page 27