...while he was sitting at the entrance of the tent in the heat of the day: (Bereishis 18:1)
It says in the Medrash (Bereishis Rabboh 48) a good door you have opened for those who pass to and fro, a good door you have opened for Geirim. The explanation is, as Avrohom Avienu has seen that it is possible to change over those who have sinned to be righteous Baalei Teshuvoh. Even if they have sinned, they can return. He understood from this, that he can also to be Migayer Nochrim and bring them under the Kanfei HaShchinoh. As it is harder to bring back a Yisroel who has sinned and been distanced, than to change over a Goy to a Yehudi. Mamrei is Gematria of Refoh and Pe'er (281). As those who pass (transgress), become returnees, it is a Refuoh - cure for their Aveiros. The Chatoim - transgressions become a beauty, as the Chazal say (Yumoh 86:2) with Teshuvoh Mei'Ahavoh the Zidinos Nasim Zechuios - transgressions become merits.
- Sefer Divrei Shmuel - Slonim
