Sayyiduna Abu Hurairah (may Allah be pleased with him) narrated from the Messenger of Allah (peace and blessings be upon him), he (peace be upon him) said: "Whoever loves these two, that is, Hasan and Husayn (may Allah be pleased with them both), has loved me, and whoever harbors enmity towards them has harbored enmity towards me."
Hadith Referenceمسند اسحاق بن راهويه / كتاب الفضائل / 557
Hadith Takhrij«ابن ماجه ، كتاب السنة ، باب فضل الحسن والحسين رضى الله عنه ، رقم : 143 . مسند احمد : 288/2 .»