Imam Jafar Sadiq (a.s.) informed Yunus b. Yaqoob – Accursed Accursed is the one who bears hatred for Ali b. Abi Talib (a.s.), because surely he did not bear hatred towards him (a.s.) until he bears hatred for Holy Prophet (s.a.w.a.) and the one who bears hatred for Holy Prophet (s.a.w.a.), Allah has cursed him in the world and the hereafter.
Wasaail al-Shia v 16 p 281