Sayyiduna Sahl bin Sa'd al-Ansari (may Allah be pleased with him) said: We were with the Messenger of Allah (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 come to give myself to you. He (peace and blessings be upon him) looked at her from top to bottom, then remained silent. Then a man stood up who had only one garment, which he had tied around his neck, and he said: If you have no need of her, then marry her to me. He (peace and blessings be upon him) said to him: "Do you have anything?" He said: No. He (peace and blessings be upon him) said: "She must be given something; go and look." He went and looked but found nothing, so he came back and said: I did not find anything. The Messenger of Allah (peace and blessings be upon him) said to him: "Go and look, even if it is an iron ring." He went, then came back and said: I did not even find an iron ring. Then he sat down, and the Messenger of Allah (peace and blessings be upon him) said to him: "What do you know of the Qur'an?" He said: Such-and-such surah and such-and-such surah. He (peace and blessings be upon him) said: "I have married you to her for what you know of the Qur'an."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 5729