عَنِ ابْنِ نُبَاتَةَ قَالَ سُئِلَ سَلْمَانُ الْفَارِسِيُّ عَنْ عَلِيِّ بْنِ اَبِي طَالِبٍ عَلَیْہِمَا السَّلَامُ قَالَ سَمِعْتُ رَسُولَ اللهِ ﷺ يَقُولُ عَلَيْكُمْ بِعَلِيِّ بْنِ اَبِي طَالِبٍ فَاِنَّهُ مَوْلَاكُمْ فَاَحِبُّوهُ وَ كَبِيرُكُمْ فَاتَّبِعُوهُ وَ عَالِمُكُمْ فَاَكْرِمُوهُ وَ قَائِدُكُمْ اِلَى الْجَنَّةِ فَعَزِّرُوهُ وَ اِذَا دَعَاكُمْ فَاَجِيبُوهُ وَ اِذَا اَمَرَكُمْ فَاَطِيعُوهُ اَحِبُّوهُ لِحُبِّي وَ اَكْرِمُوهُ لِكَرَامَتِي مَا قُلْتُ لَكُمْ فِي عَلِيٍّ اِلَّا مَا اَمَرَنِي بِهٖ رَبِّي
Asbagh Ibn Nubaatah chronicles, “Salman al-Farsi (al-Muhammadi) was asked about Ali Ibn Abi Talib (peace be on them both). He replied, ‘I heard the Messenger of Allah (peace be on him and his progeny) say,
‘It is obligatory upon you (to follow) Ali Ibn Abi Talib (peace be on them both). For surely, he is your master, so love him; he is your elder, so follow him; he is your learned scholar, so respect him and he is your guide to paradise, so help him. When he calls you, respond to him. When he orders you, obey him. Love him for my love (i.e. if you love me, love him) and respect him for my respect. I did not say to you anything about Ali (peace be on him) except whatever my Lord has ordered me to say.”
Note:
1) The Holy Quran has already guaranteed about the words of the Messenger of Allah (peace be on him and his progeny) by saying that “He (peace be on him and his progeny) does not speak of his own desire. It is naught but a revelation inspired upon him (peace be on him and his progeny).” (Surah Najm (53): Verses 3 and 4). Yet, he (peace be on him and his progeny) had to repeat the point that whatever I am saying is on the instructions of my Lord because the hypocrites kept questioning his (peace be on him and his progeny) intentions and instigated the people against Ameerul Momineen Ali Ibn Abi Talib (peace be on them both).
2) It is really surprising that despite the express prohibition of the Messenger of Allah (peace be on him and his progeny) of calling Salman as al-Farsi, rather, to address him as al-Muhammadi, we see that writers and speakers often addressing him as al-Farsi. We must try our best to implement this instruction of the Messenger of Allah (peace be on him and his progeny).
References:
1. Kanz al-Fawaaed, vol. 2, p. 56
2. Behaar al-Anwaar, vol. 27, p. 112, H. 86