Abu Hazim heard Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) saying: I was with the people in the company of the Prophet (peace and blessings be upon him) when a woman stood up and said: I have offered myself to you as a gift, so give your opinion concerning me. Then a man stood up and said: O Messenger of Allah (peace and blessings be upon him)! Marry me (to her). But he (peace and blessings be upon him) gave no reply. Then the woman stood up again and said: I have offered myself to you as a gift, so give your opinion concerning me. Then that man said: Marry me (to her). Then the woman stood up a third time, and the Messenger of Allah (peace and blessings be upon him) said to the man: "Do you have anything?" He said: No. He (peace and blessings be upon him) said: "Go and look." But despite searching he found nothing. He (peace and blessings be upon him) said: "Go and look, even if only for an iron ring." So the man went, then came back and said: I found nothing at all. He (peace and blessings be upon him) asked: "Do you know any of the Qur'an?" He said: I know such-and-such surahs. He (peace and blessings be upon him) said: "Go, I have married you to her in return for the Qur'an that you have."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14359