قَالَ النَّبِيُّ ﷺ وَ اَخَذَ بِيَدِ عَلِيٍّ ؑ مَنْ زَعَمَ اَنَّهٗ يُحِبُّنِي وَ لَا يُحِبُّ هٰذَا فَقَدْ كَذَبَ
The Holy Prophet (peace be on him and his progeny) took the hand of Ali (peace be on him) and declared,
“Whoever thinks that he loves me but does not love him (viz. Ali) then indeed he has lied.”
References:
The love of Ali Ibn Abi Talib is essential; Allah will not accept any good deed until one is questioned about this love, determining the acceptance of their actions.
Follow and love Ali Ibn Abi Talib, as he is your master, elder, scholar, and guide to paradise. Respond to his calls and obey his commands.
Loving Ali (peace be on him) is equated with loving the Messenger of Allah and Allah Himself, while harboring malice against him is akin to opposing them.
حب في الله وبغض في الله هما أساس ولاية الله، ولا يُنال طعم الإيمان إلا بذلك، فالمؤاخاة يجب أن تكون في الله لا للدنيا.