Musannaf Ibn Abi Shaybah 27504 — A man entering a house with no one

Nafi' said that Sayyiduna Ibn Umar (may Allah be pleased with them both) said, concerning a man who enters a house or a mosque in which there is no one, that he should say: 'As-salamu alayna wa ala ibadillahis-salihin' (Peace be upon us and upon the righteous servants of Allah).