عن قتادة قال : قال النبي صلى الله عليه وسلم: إذا دخلتم بيتًا فسلموا على أهلِهِ فإذا خرجتم فأودعوا أهله بسلام (شعب الايمان للبيهقي رقم 8459)
Hadhrat Qataadah (Rahimahullah) reports that Rasulullah (Sallallahu Alaihi Wasallam) said: “When you enter a home, then make salaam to its inmates; and when you leave (the home), then leave your salaam as a trust with the people of the home (i.e. make salaam to the people when leaving).”
N.B. Nabi (Sallallahu Alaihi Wasallam) has taught us to make salaam when leaving the home and he said: “Leave your salaam as a trust with the people of the home”. Generally when one keeps a trust by someone, he comes back at a later period to receive it. Therefore when one leaves the trust of salaam with the people of the home, as though one is taking a good omen and placing his hope in Allah Ta’ala’s mercy that Allah Ta’ala will soon return him to the home he is leaving.