Analysis:

This quatrain is a passionate plea from a lover to their beloved, who is likened to a king or queen of beauty.

Unrequited Love: The speaker is clearly suffering from unrequited love, as they plead with their beloved to end their cruelty.
The Power of Beauty: The beloved is portrayed as having immense power, capable of issuing decrees and controlling the natural world (as symbolized by the cypress tree playing the lute).
Imploring for Mercy: The speaker begs for an end to their suffering, asking for a respite from the beloved's cruelty.
Universal Themes: The themes of love, loss, and the power of beauty are universal and timeless. The reference to both Islamic law (Shariah) and a khan's edict suggests a broader context, indicating that the speaker's suffering transcends cultural or religious boundaries.

Deeper Meaning:

This quatrain speaks to the depths of human emotion, particularly the pain of unrequited love. The speaker's plea is a desperate cry for relief from their suffering. The image of the cypress tree playing the lute is a beautiful metaphor for the power of music to express emotions, and the speaker's desire for their beloved to be moved by their heartfelt plea.

Themes:

Unrequited love: The central theme is the pain of unrequited love.
Power and beauty: The beloved is portrayed as having immense power and beauty.
Imploring for mercy: The speaker begs for an end to their suffering.
Universality of love: The themes are universal, transcending cultural boundaries.

This quatrain is a powerful and timeless expression of the human heart. It captures the intensity of love, the pain of rejection, and the enduring hope that even the most powerful can be moved by love.