Musnad Ahmad 1153:363

Hassan narrated to us, Ibn Lahi'ah narrated to us, Ja'far ibn Rabi'ah narrated to us, from Ibn Shihab, from 'Urwah ibn al-Zubayr, from 'Aishah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Any woman who marries without the permission of her guardian, her marriage is void. If he has consummated with her, then she is entitled to her dowry for what he has enjoyed of her private parts. And if they dispute, then the Sultan (ruler) is the guardian of the one who has no guardian."