M4:64 — بر همه زهر و برو تریاق بود / آن عوان پیوند آن مشتاق بود

This couplet is the pivot point in a story about a lover who, fleeing a brutal night watchman (ʿavān), accidentally finds his beloved in the garden where he takes refuge. Overjoyed, the lover begins to pray for the very guard who terrified him moments before.

Rumi uses this moment to introduce a core philosophical principle: the relativity of good and evil. An event or a person is rarely absolutely good or bad; its quality depends on the context and the outcome for a specific individual. The watchman's actions, which would be a "poison" for any other law-breaker, became a "theriac" (taryāq)—a legendary antidote—for the lover, curing his suffering of separation.

The second line reinforces this by stating that the guard, an agent of separation and punishment, paradoxically became the "link" (peyvand) that connected the yearning lover (mushtāq) to his goal. This illustrates the Qur'anic verse cited in the section title: "Perhaps you hate a thing and it is good for you" (2:216). Rumi teaches that what appears to be a calamity can be a hidden grace, a harsh instrument delivering a divine gift.