It is mentioned in Basairud Darajat from Fazal bin Isa that: Once I and my father came to Imam Ja’far Sadiq (a.s.) and my father asked: Is it true that the Holy Prophet (S) has said that Salman is from us Ahlul Bayt (a.s.)? Imam (a.s.) replied: “Yes.” My father asked: “Was he from the progeny of Abdul Muttalib?” Imam (a.s.) said: “He was from us, Ahlul Bayt (a.s.).” Again he asked the same question and got the same answer. Again my father said: “I don’t get you.” Imam (a.s.) said: “You should know that he was from us, Ahlul Bayt (a.s.).”
And the Imam pointed to his chest and said, “It is not as you think. The Almighty Allah has indeed created our essence from Illiyyin and created the essence of our Shia from one grade lower than that. So he is from us and the essence of our enemies is created from Sijjin and the essence of their friends is created from one grade lower than that. Therefore they are from them and Salman is better than Luqman.”