Medea's opening speech establishes her situation and motivations. It outlines her plight in a manner designed to elicit sympathy not only for her current position but also for the vengeance that she is plotting.
Her speech follows many of the standard rhetorical patterns of the period. She begins by soliciting the goodwill of her audience, primarily by saying that they need to avoid prejudging her and instead listen to her words and consider her situation. She does this by an extended comparison of the pitiful life of women with the freedoms enjoyed by men. She points out that a woman needs to marry and is despised if she divorces, even though she cannot learn much about her husband before marriage and he may turn out to be abusive. She points out that men have freedom to associate with other people and even take lovers after being married but that women are, to a great degree, lonely, isolated, and dependent on their husbands. Although she gives a somewhat misleading account of her relationship with Jason and omits some crucial information about her past, she is truthful in saying that she has been abused.
The final part of her speech is a direct foreshadowing of her future actions. She says that despite women being weak, they are strong and relentless when hurt in matters of love, and she explicitly promises to punish Jason and his bride, saying of herself,
... when she’s hurt in love,
her marriage violated, there’s no heart
more desperate for blood than hers.