Analysis:

This quatrain by Saadi Shirazi is a scathing indictment of a powerful person who has abused their authority.

The Return of the Oppressor: The quatrain seems to address a ruler or a powerful individual who has returned after committing atrocities.
The Hypocrisy of Justice: The speaker is expressing disbelief that the oppressor has returned without facing any consequences. The irony is that the oppressor is seen as 'blameless' even after committing such heinous acts.
A Question of Morality: The quatrain raises profound questions about morality and justice. It suggests that a system that allows the powerful to go unpunished is fundamentally flawed.

Themes:

Injustice and Oppression: The central theme is the injustice faced by the oppressed.
Hypocrisy and Corruption: The quatrain highlights the hypocrisy of a system that allows the powerful to escape punishment.
Morality and Ethics: The poem raises profound questions about morality and ethics.

Deeper Meaning:

This quatrain is a powerful critique of societies where the powerful are above the law. It is a timeless message that resonates with people who have experienced oppression and injustice. The speaker's bitter sarcasm and irony highlight the deep-seated anger and frustration felt by the oppressed.

This quatrain is a call for justice and a condemnation of those who abuse their power. It is a reminder that even the most powerful individuals can be held accountable for their actions.