Abdullah bin Amr, from MUSA BIN JAAFAR (ASWS), from his father (6th Imam (ASWS)), from his grandfather (5th Imam (ASWS)), who said:
Jibraeel came to the MESSENGER OF ALLAH (SAWW) and said, "O MOHAMMAD (SAWW)! ALLAH (SWT) orders you to love ALI BIN ABI TALEB (ASWS) since ALLAH (SWT) Himself loves ALI BIN ABI TALEB (ASWS) and He loves those who love ALI BIN ABI TALEB (ASWS)."
Jibraeel then asked, "O MESSENGER OF ALLAH (SAWW)! Who hates ALI BIN ABI TALEB (ASWS)?"
"Those who incite people against ALI (ASWS)," The PROPHET (SAWW) replied.
(Ref: Bihar Al-Anwar 42:306 & 39:285)