810/1055 (Hasan al-Isnad) from Abdullah ibn Umar who said: "When one enters an uninhabited house, let him say: Peace be upon us and upon the righteous servants of Allah."

811/1056 (authentic chain) From Ibn Abbas who said: "Do not enter houses other than your own until you seek permission and greet their inhabitants" [النور: 27] , and he made an exception from that, saying: "There is no blame upon you for entering houses not inhabited in which there is some belonging of yours... " up to His saying: "you conceal" [النور: 29] .