Al-Hasan Ibn Ali al-Khazzaaz reports, “I heard Imam al-Reza (a.s.) say,
‘Surely, from among those who claim the love of us Ahl al-Bait (a.s.) is the one who is a greater mischief against our Shias than the Dajjaal (anti-Christ).’ I asked, ‘How come?’ He (a.s.) replied, ‘By befriending our enemies and bearing enmity against our friends. When this is the case, truth will be mixed with falsehood and the matter will become confused. Thereafter, a believer will not be distinguished from a hypocrite.”
Sefaat al-Shiah by Shaikh al-Sadoog (ra.), p. 8, II. 14