מדרש על דברים 19:4

(Devarim 19:4) "And this is the dvar of the slayer": From here they ruled: If a slayer fled to his city of refuge and the people of that city wished to honor him, he must tell them: "I am a slayer." If they persist, he may accept their homage, (it being written "And this is dvar [lit., "the word"] of the slayer" [i.e., he must tell them "I am a slayer"]).