In the establishing of the Wall over the Treasure, there is sufficiency in this meaning for the "People of Intellect" (Ulul Albab).

Among the proofs that it is not permissible for a believer to abandon Dissimulation among the Opposites (Al-Addad) as long as he is within the Human Shirt (Al-Qamis al-Bashari), is what was reported by the author of the book Haqā'iq Asrār al-Dīn (The Truths of the Secrets of Religion)—may Allah sanctify him.

Mufaddal said:

"I asked The Scholar [Imam al-Sadiq]—peace be from him—regarding a believer being a slave owned by another believer or by a disbeliever, and the reason behind that?"

He said: "The meaning of slavery is of two aspects. As for the first aspect: a believer may indeed be a slave owned by a believer, but he is never [spiritually] a believer-slave to a disbeliever."

I said: "My Master, what is the cause and the reason for a believer to be the slave of a believer?"

He said: "The cause is that this slave, in the First Primordial Scattering (Al-Dharw al-Awwal), was a brother to the believer who now owns him in the Second Scattering.