The Messenger of Allah said:
“Loving Ali is the sign of belief, and hating Ali is the sign of
hypocrasy.”
Sunni references:
- Sahih Muslim, v1, p48;
- Sahih Tirmidhi, v5, p643;
- Sunan Ibn Majah, v1, p142;
- Musnad Ahmad Ibn Hanbal v1, pp 84,95,128
- Tarikh al-Kabir, by al-Bukhari (the author of Sahih), v1, part 1, p202
- Hilyatul Awliya’, by Abu Nu’aym, v4, p185
- Tarikh, by al-Khateeb al-Baghdadi, v14, p462
This tradition of Prophet was popular to the extent that some of the companions used to say:
“We recognized the hypocrites by their hatred of Ali.”
Sunni references:
- Fada’il al-Sahaba, by Ahmad Ibn Hanbal, v2, p639, Tradition #1086
- al-Istiab, by Ibn Abd al-Barr, v3, p47
- al-Riyad al-Nadirah, by al-Muhib al-Tabari, v3, p242
- Dhakha’ir al-Uqba, by al-Muhib al-Tabari, p91
Also Muslim in his Sahih narrated on the authority of Zirr that:
Ali (RA) said: By him who split up the seed and created
something living, the Apostle (may peace and blessing be upon
him) gave me a promise that no one but a believer would love
me, and none but a hypocrite would nurse grudge against me.
Sahih Muslim, English version, Chapter XXXIV, p46, Tradition #141
Aal-e-Qutub Aal-e-Syed Abdullah Shah Ghazi 