Muslim is the one from whose tongue

 Prophet Muhammad (Peace Be Upon Him) said: “The Muslim is the one from whose tongue & hand the Muslims are safe.” [Bukhari, 10; Muslim, 40]. And he (PBUH) said, in a lengthy hadeeth in which he (PBUH) enjoined a number of virtues, “… If you cannot do that, then leave people alone (and do not offend them), for that is an act of charity that you do for yourself.” [Bukhari, 2382; Muslim, 84].