Abu Sa’eed Al-Khudri (a Companion) narrated that there was an altercation between Khaalid ibn Al-Waleed and ‘Abdur-Rahmaan ibn ‘Awf, so Khaalid, reviled him. The Prophet of Allah, sallallaahu ‘alayhi wa sallam, said: “Do not curse my Companions, for if one of you spent [as much as] Mount Uhud in gold, it would not be equal to the two handfuls of one of them, or even half of that [of food he spends in charity].”
The intent of the Prophet’s statement: “My Companions,” is his closest Companions, the ones who became Muslim before the conquest of Makkah, and accompanied him for a long time, and fought, gave charity, migrated, and helped the Prophet of Allah, sallallaahu ‘alayhi wa sallam. Thus, the early Companions from the Muhaajiroon and Ansaar are better than the rest of the Companions after them. This meaning is indicated by the fact that the Prophet of Allah, sallallaahu ‘alayhi wa sallam, was speaking to Khaalid ibn Al-Waleed and he was one of the Companions of the Prophet of Allah, sallallaahu ‘alayhi wa sallam, at the time.
Ibn Hajar said: “The prohibition of the Prophet of Allah, sallallaahu ‘alayhi wa sallam, against some of the later Companions cursing those Companions who became Muslim before them, necessitates that those who came after the Prophet of Allah, sallallaahu ‘alayhi wa sallam, are even more strongly prohibited from cursing those Companions who were before them.”
If this is what the Prophet of Allah, sallallaahu ‘alayhi wa sallam, said to Khaalid ibn Al-Waleed and the other Companions who become Muslim after Hudaybiyah, then what do you think he, sallallaahu ‘alayhi wa sallam, would say about a person that was not from his Companions and was speaking badly about them?