The MESSENGER OF ALLAH (SWT) said:
ALLAH (SWT) has made it obligatory to obey me and He has forbidden you from disobeying me. ALLAH (SWT) has ordered you to follow my commands.
ALLAH (SWT) has made it obligatory to obey ALI (ASWS) after me, just (ASWS) he enjoined you to obey me. And ALLAH (SWT) has forbidden you from disobeying ALI (ASWS), just (ASWS) he has forbidden you from disobeying me.
ALLAH (SWT) has assigned ALI (ASWS), the Commander of the Believers, (ASWS) my brother, my minister, my successor, and my heir.
ALI (ASWS) is from me and I am from him, Loving ALI (ASWS) is Iman and hating ALI (ASWS) is kufr.
Loving ALI (ASWS) is loving me, and hating him is hating me.
ALI (ASWS) is the master of whomsoever I am the master, and I am the master of every Muslim.
ALI (ASWS) and I are the fathers of this nation.
(Ref: AmaALI of Sadouq 22, Bihar Al-Anwar 38:91)