Khalid bin Ma'dan (may Allah have mercy on him) narrates: Al-Miqdam bin Ma'dikarib (may Allah be pleased with him) and Amr bin al-Aswad came to Qinnasrin. Mu'awiyah (may Allah have mercy on him) said to al-Miqdam: Do you know that Hasan bin Ali has passed away? Al-Miqdam recited "Inna lillahi wa inna ilayhi raji'un (We belong to Allah and to Him we return)." Mu'awiyah said to him: Do you consider it a calamity? He said: Why should I not consider it a calamity, when the Messenger of Allah (peace and blessings be upon him) seated him in his lap and said: "This one is from me, and Husayn is from Ali."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2615