The Hesiod poem in which Pandora opens the famous container and releases troubles into the world is Works and Days.
Works and Days is a didactic poem traditionally attributed to Hesiod and generally dated to the late eighth or early seventh century BCE. It combines advice about farming, justice, household conduct, and sailing with myths explaining why human life involves hardship.
In its Pandora episode, Zeus has the gods create a woman as part of his punishment of humanity after Prometheus steals fire. Pandora receives gifts from the gods and later opens a large storage jar, allowing evils and diseases to escape. Hope remains inside, according to the poem’s wording.
The modern expression “Pandora’s box” comes from later translation and interpretation. Hesiod’s Greek uses the word pithos, meaning a large jar or storage vessel, not a small box. The poem therefore provides the central literary source for the popular myth while also differing from its modern retelling.