Sayyiduna Salman (al-Farisi) (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) said about Sayyiduna Hasan and Sayyiduna Husayn: "Whoever loves them both, I love him; and whomever I love, Allah loves; and whomever Allah loves, He will admit into the Gardens of Bliss. And whoever hates them both or wrongs them, I hate him; and whomever I hate, Allah hates; and whomever Allah hates, He will admit into the punishment of Hell, and for him is an everlasting punishment."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2642