Abdullah bin Ahmad bin Aamer, from his father, from IMAM ALI BIN MUSA - REDHA (ASWS), from IMAM MUSA BIN JAAFAR BIN MOHAMMAD (ASWS) , from IMAM MOHAMMAD BIN ALI (ASWS), from IMAM ALI BIN HUSAIN (ASWS) , from IIMAM HUSAIN BIN ALI (ASWS) , from HAZRAT ALI BIN ABI TALEB (ASWS), from the MESSENGER OF ALLAH (SAWW), who said:
Of whomsoever I am his master, this ALI (ASWS) is his master. O ALLAH (SWT)! Befriend those who befriend him, and antagonise those who antagonise him. Disappoint those who abandon him, and support those who support him.
(Ref : Bihar Al-Anwar 37:222. Sahifatol Redha 172. Amaali of Tousi 1:260:353)