Sahih Bukhari Volume 007, Book 062, Hadith Number 024.
Narrated By Sahl bin Sad As-Sa'idi : A woman came to Allah's Apostle and said, "O Allah's Apostle! I have come to give you myself in marriage (without Mahr)." Allah's Apostle looked at her. He looked at her carefully and fixed his glance on her and then lowered his head. When the lady saw that he did not say anything, she sat down. A man from his companions got up and said, "O Allah's Apostle! If you are not in need of her, then marry her to me." The Prophet said, "Have you got anything to offer?" The man said, "No, by Allah, O Allah's Apostle!" The Prophet said (to him), "Go to your family and see if you have something." The man went and returned, saying, "No, by Allah, I have not found anything." Allah's Apostle said, "(Go again) and look for something, even if it is an iron ring." He went again and returned, saying, "No, by Allah, O Allah's Apostle! I could not find even an iron ring, but this is my Izar (waist sheet)." He had no rida. He added, "I give half of it to her." Allah's Apostle said, "What will she do with your Izar? If you wear it, she will be naked, and if she wears it, you will be naked." So that man sat down for a long while and then got up (to depart). When Allah's Apostle saw him going, he ordered that he be called back. When he came, the Prophet said, "How much of the Quran do you know?" He said, "I know such Sura and such Sura," counting them. The Prophet said, "Do you know them by heart?" He replied, "Yes." The Prophet said, "Go, I marry her to you for that much of the Quran which you have."