M3:2563 — خلق جمله علتی‌اند از کمین / یار علت می‌شود علت یقین

This couplet appears in a section where Rumi is discussing the deceptive nature of the lower self (nafs) and the necessity of distinguishing true spiritual guidance from false. The nafs is likened to a cunning adversary, and the preceding verses emphasize that only divine inspiration or the guidance of a true spiritual master (like David, or a shaykh who embodies divine truth) can overcome its deceptions.

Here, Rumi extends this warning to human companions. He states that 'all people' (khalq-e jomle) are fundamentally a 'sickness' (ʿellat) lying in 'ambush' (az kamīn). This isn't a blanket condemnation of humanity, but rather a cautionary note for the spiritual seeker. Most people, being entangled in their own nafs, desires, and worldly concerns, inadvertently become sources of distraction and spiritual contamination. Their company, far from being helpful, will only 'become a sickness' (yār ʿellat mī-shavad), a 'certain affliction' (ʿellat yaqīn), for the seeker.

The implication is that unless one has attained the spiritual discernment of a true master, one must be extremely cautious about whom one takes as a friend or guide. The 'sickness' here refers to the spiritual maladies that hinder one's journey towards God, such as heedlessness, attachment to the world, egoism, and doubt. The couplet reinforces the idea that true guidance comes from a purified source, not from the general populace, which is itself in need of healing.