Deuteronomy 23:8 "Do not despise an Egyptian because you were a stranger in his land"

The Torah forbids an Egyptian convert from marrying freely into the Jewish people until the third generation.

The hundreds of years of cruel slavery in Egypt affected both nations. Nevertheless, despite the hardships in Egypt, the Torah appreciates that Jacob and his sons were given refuge in Egypt. Also, it was in Egypt that the Jewish people developed into a nation to be chosen by HaShem.

Therefore, we are commanded not to totally reject an Egyptian that converts to Judaism. The third generation of such converts may marry freely among the Jewish people.