by R. Ari Enkin
Our sages teach that one should not enter any home, even one’s own, without knocking first. As Rabbi Shimon bar Yochai teaches: “There are four things that God hates that I also don’t like…a person who enters his own home suddenly without knocking, and it goes without saying, one who enters his neighbor’s house without knocking.” Vayikra Rabba 21:8. Similarly, Rabbi Akiva included this in the seven instructions he gave his son Yehoshua: “My son…do not enter your house suddenly, and how much more so, your friend’s house.” Pesachim 112a. The Midrash says that Rav Yochanan would clear his throat before entering Rav Hanina’s home as a way of announcing his arrival. Vayikra Rabba 21:8. See also Derech Eretz Rabba 5; Pesachim 112a; Nidda 16b.
We are taught that knocking before entering a home is reminiscent of the ways of God. When God was looking for Adam following the sin of the forbidden fruit, He first called out “Where are you?” before entering the Garden of Eden. Knocking also recalls the Kohen Gadol’s robe, which had bells along its hem in order to “announce” the Kohen’s arrival wherever he went. Exodus 28:33-35. It is taught that knocking before entering a home is among the character traits of the wise. Derech Eretz Rabba 5:2, 3. Knocking before entering a home (or a room) also shows sensitivity to those in the home and allows them to better prepare for and receive the one who is entering. Torah Temima, Bereishit 3:9.
It goes without saying that one may not enter another person’s home without permission – something we learn from Moshe Rabbeinu, who would not even enter the Ohel Moed (Tent of Meeting) without first being called upon to do so by God. Midrash Lekach Tov, Vayikra 1:1. Even an officer of the court may not enter someone’s home without permission. This is true even when he is in the service of the court, such as to extract a pledge or collateral from a debtor. Rambam, Hilchot Malveh V’loveh 2:2; CM 97:6.