Is a woman allowed to take an oath?

It is permissible for a woman to swear an oath in matters that are lawful. The proof for this is the narration from Aisha (may Allah be pleased with her) that the Prophet (peace be upon him) used to know her pleasure and anger from her oath. If she was pleased, she would say: "No, by the Lord of Muhammad." And if she was angry, she would say: "No, by the Lord of Abraham."