(If nobody is present in the house then one should say: Peace be upon you O Messenger of Allah and Allah's Mercy and blessings) while doing Sharh of this Mullah Ali Qari (rah) writes: “Meaning, because his (Peace Be Upon Him) soul, is present in the house of the Muslims. [Mullah Ali Qari, Sharah ush-Shifah, Volume 002, Page No. 117]