From the route of Abu Sa^id Sa^d bin Malik bin Sinan al-Khudriyy, may Allah accept his deeds, who said that the Messenger of Allah, sallallahu ^alayhi wa sallam, said:
<<It is unlawful for one to harm another and it is unlawful to harm one another.>>
This Hadith is Hasan and narrated by Ibn Majah and ad-Daraqutniyy and others with a Musnad chain of narration (the chain goes back to the Prophet).
Malik narrated it in the Muwatta‘ in a Mursal chain of narration from the route of ^Amr bin Yahya from his father from the Prophet, sallallahu ^alayhi wa sallam, and skipped Abu Sa^id and the Hadith has routes of narration which strengthen one another.