Analysis:

This quatrain by Saadi Shirazi presents a complex and paradoxical situation of love and pain. The speaker seems to be in a masochistic relationship, finding pleasure in the pain inflicted by their beloved, even if it's through the actions of their enemy. Let's break down each line:

Line 1: چون حال بدم در نظر دوست نکوست

"Since my ill state pleases my beloved,"
Here, the speaker reveals a disturbing truth: their beloved finds pleasure in seeing them suffer. This suggests a dynamic where the beloved holds power over the speaker, and the speaker derives a perverse satisfaction from this power imbalance.

Line 2: دشمن ز جفا گو ز تنم برکن پوست

"My enemy, through cruelty, might as well strip me bare."
The speaker invites the enemy to inflict even greater pain, suggesting a masochistic desire for suffering. The enemy is seen as an extension of the beloved, and their cruelty is somehow linked to the beloved's pleasure.

Line 3: چون دشمن بیرحم فرستادهٔ اوست

"Since my cruel enemy is sent by my beloved,"
The speaker explicitly states that the enemy is acting at the behest of the beloved. This reinforces the idea that the pain inflicted by the enemy is somehow connected to the love they feel for the beloved.

Line 4: بدعهدم اگر ندارم این دشمن دوست

"I would be disloyal if I didn't cherish this enemy-lover."
The speaker concludes by arguing that they would be disloyal to their beloved if they did not appreciate the pain inflicted by their enemy. This further emphasizes the paradoxical nature of the love they feel.

Themes explored in the quatrain:

Masochism: The speaker seems to derive pleasure from pain, particularly when it is inflicted by their beloved or at their behest.
Power dynamics: The beloved holds a significant amount of power over the speaker, and the speaker is willing to submit to this power.
Paradoxical love: The love described is paradoxical, as it involves both pleasure and pain, loyalty and betrayal.

This quatrain explores the darker side of love, where the lines between love and pain, pleasure and suffering, become blurred. The speaker's acceptance of their suffering, even when it is inflicted by their enemy, highlights the complex and often irrational nature of human emotions.