Sakhtiyani (Allah have mercy on him) said: “Whoever loves Abu Bakr has upheld the religion, whoever loves Umar has made the way clear, whoever loves ‘Uthman is enlightened by the light of Allah, and whoever loves Ali has taken the firmest handhold. Whoever speaks well of the Companions of Allah's Messenger (peace be upon him) is clear of hypocrisy. But whoever belittles any one of them or dislikes (any one of them) for something he did, then he is a heretic, an opponent of the Sunnah and the Righteous Predecessors (the Salaf), and it is feared that none of his deeds will be raised to the heavens until he loves all of (the Companions) and his heart is clear towards them.” – Ibn Abi Zamanin, Usul Al
