Salman the Persian, who was a man of great strength. The Emigrants said, “Salman is one of us,” while the Helpers said, “Salman is one of us.” The Prophet ﷺ then declared, “Salman is one of us—the People of the Household.” (1)

Kathir is regarded as discarded (matrūk).

Hammad ibn Salamah narrated from Thabit, from Mu‘awiyah ibn Qurrah, from ‘Aidh ibn ‘Amr:
Abu Sufyan once passed by Salman, Bilal, and Suhayb together with a group of believers, and they said, “The swords of Allah have not yet taken their full due from the neck of the enemy of Allah.” Abu Bakr replied, “Do you say this to the elder and chief of Quraysh?!” He then went to the Prophet ﷺ and informed him. The Prophet ﷺ said, “O Abu Bakr! Perhaps you have angered them; if you have angered them, you have angered your Lord.” Abu Bakr went back to them and said, “My brothers, did I anger you?” They answered, “No, O Abu Bakr. May Allah forgive you.” (2)

Al-Waqidi said: The first military expedition in which Salman the Persian took part was the Battle of the Trench.

Ahmad records in his Musnad: Ibn Numayr narrated to us, Sharik narrated to us, Abu Rabi‘ah narrated to us, from Ibn Buraydah, from his father, traced back to the Prophet ﷺ: “Allah loves four of my Companions, and He has commanded me to love them: ‘Ali, Abu Dharr, Salman, and al-Miqdad.” (3)

This report is transmitted solely by Abu Rabi‘ah.