It is narrated from Sayyiduna Miswar bin Makhramah (may Allah be pleased with him) that Hasan bin Hasan (bin Ali) sought his daughter's hand in marriage. Miswar (may Allah be pleased with him) told him to meet him at the time of Isha. When they met, Miswar praised and glorified Allah and then said: To proceed: By Allah, no lineage, tie or relationship by marriage is more beloved to me than your lineage, tie and relationship by marriage. But the Messenger of Allah (peace and blessings be upon him) said: "Fatimah is a piece of me; what distresses her distresses me, and what gladdens her gladdens me. And on the Day of Resurrection all ties will be severed except my lineage, my tie and my relationship by marriage." And you already have her daughter (the granddaughter of Sayyidah Fatimah, may Allah be pleased with her) in your marriage; if I were to marry my daughter to you as well, that would distress her (Sayyidah Fatimah, may Allah be pleased with her). So he went away accepting his excuse. This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.