לא תתעב אדמי כי אחיך הוא לא תתעב מצרי כי גר היית בארצו... דור שלישי יבא להם בקהל ד'
Understandably, we would not want to accept the children of a convert from those nations who have persecuted us. The Torah’s line of thinking is different than ours. Hashem has enjoined us to take a positive view of the descendants of these nations. Edom is “family,” and Egypt provided food and lodging for Yaakov Avinu and his family. What happened later is a different story. It does not absolve us of the obligation to show gratitude. Nonetheless, it takes three generations after conversion for their base nature to be expunged. The Sefer HaChinuch explains the shoresh, root, of this mitzvah….
