It is narrated from Sayyiduna Dumayrah bin Abi Dumayrah (may Allah be pleased with him) that a man came to the Prophet (peace and blessings be upon him) and said: O Messenger of Allah, marry me to such-and-such a woman. He (peace and blessings be upon him) said: "What do you have to give her as a dowry (mahr) and as a gift?" He said: I have nothing. He (peace and blessings be upon him) said: "Whose is this ring?" He said: Mine. He (peace and blessings be upon him) said: "Then give her this." And he (peace and blessings be upon him) married him (to her), and he married another man, who had nothing, in return for (teaching) Surah al-Baqarah.
Hadith Referenceالمعجم الكبير للطبراني / باب الضاد / 8122
It is narrated from Sayyiduna Dumayrah bin Abi Dumayrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever does not show mercy to our young and does not recognise the right of our elders is not one of us; and whoever deceives us is not one of us; and a believer is not a believer until he loves for his believing brothers what he loves for himself."
Hadith Referenceالمعجم الكبير للطبراني / باب الضاد / 8123