alkafi-14921Vol. 8, p. 162
سَمِعْتُ أَبَا عَبْدِ اللَّهِ ع يَقُولُ آخَى رَسُولُ اللَّهِ ص بَيْنَ سَلْمَانَ وَ أَبِي ذَرٍّ وَ اشْتَرَطَ عَلَى أَبِي ذَرٍّ أَنْ لَا يَعْصِيَ سَلْمَانَ.
The Rasool (saww) established brotherhood between Salman (ra) and Abu Dharr (ra), and stipulated a condition upon Abu Dharr (ra) that he (ta) would not disobey Salman (ra) (as a younger to an elder brother).