Sayyiduna Sahl bin Sa'd (may Allah be pleased with him) relates: I was present in the gathering with the Prophet (peace and blessings be upon him) when a woman came to him (peace and blessings be upon him) and said: O Messenger of Allah, I have given myself to you, so decide about me as you see fit. Then a man stood up and said: O Messenger of Allah, if you have no need of her, then marry her to me. The narrator said: The Messenger of Allah (peace and blessings be upon him) remained silent. Then the woman stood up and repeated the same thing. The man said: O Messenger of Allah, if you have no need of her, then marry her to me. The Messenger of Allah (peace and blessings be upon him) said to the man: "Do you have anything you could give her?" He said: No. He (peace and blessings be upon him) said: "Go and search for something." He went, then came back and said: O Messenger of Allah, I did not find anything. He (peace and blessings be upon him) said: "Go and search, even if it is only an iron ring." He went, then came back and said: O Messenger of Allah, I did not find anything, not even an iron ring. The Messenger of Allah (peace and blessings be upon him) said: "Do you know anything of the Qur'an?" He said: Yes, such-and-such surah and such-and-such surah. He (peace and blessings be upon him) said: "Go, I have married you to her for what you have of the Qur'an."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5894