Silsilat al-Ahadith al-Sahihah

Sayyiduna Abu Hurairah (may Allah be pleased with him) says: When I see Sayyiduna Hasan (may Allah be pleased with him), tears flow from my eyes. The reason is that one day the Noble Prophet (peace and blessings of Allah be upon him) came out while I was in the mosque. He took my hand, and I walked with him. He did not speak to me until we reached the market of Banu Qaynuqa'. He walked around there and looked here and there, then returned, and I was with him until we reached the mosque. There, he sat down with his knees drawn up and said: "Where is the little child? Call the little one to me." So Sayyiduna Hasan (may Allah be pleased with him) came running, fell into his lap, and began to put his hand in his beard. The Prophet (peace and blessings of Allah be upon him) opened his mouth and put Hasan's mouth into his own mouth, then said: "O Allah! I love him, so love him, and love the one who loves him."