The Prophet (PBUH) heard both sides of the disputing parties, even if one of them was not Muslim

“A Jew was selling some goods, and was given something for one of his goods that he disliked or did not approve of. He said: ‘No, by He who has chosen Moses over all humanity.’ A man from the Ansaar heard him and struck his face, saying: ‘You have the audacity to say, ‘By He who has chosen Moses over all humanity,’ while the Messenger of Allah, sallallaahu ‘alayhi wa sallam, is living among us?’ The Jewish man then went to the Messenger of Allah, sallallaahu ‘alayhi wa sallam, and said: ‘O Abu Al-Qaasim, I have protection and a covenant, and so-and-so slapped my face.’ The Messenger of Allah, sallallaahu ‘alayhi wa sallam, said: ‘Why did you slap his face?’ He said: ‘O Messenger of Allah, he said: ‘By He who has chosen Moses over humanity, while you are living among us.’At that, the Messenger of Allah, sallallaahu ‘alayhi wa sallam, became so angry that it was visible on his face, then said: ‘Do not differentiate between Allah’s Prophets. The trumpet will be blown, and whoever is in the heavens and in the earth will be struck unconscious, except those whom Allah Wills. Then it will be blown again, and I will be the first to be resurrected, and will find Moses holding fast to Allah’s throne. I would not know if he has been struck unconscious as well and has been awakened before me, or was one of those whom Allah has given an exception to [by not causing them to faint].