הלכה אויף בראשית 17:5

A proselyte brings and reads, as it is said to Abraham, "A father of the many peoples I have made you..." This means that he was the father to the entire world that entered under the wings of the Shechina, and the promise was to Abraham first that his children would inherit the land. So too, priests and levites bring and read because they have open cities.

If someone does not recite the Shema morning and evening, or one who publicly violates the mitzvos, cannot be counted for Zimun. A true convert may be counted for Zimun and he may lead and say: "For your parceling out as a heritage to our fathers" because it is written about our father, Abraham, "A father to many nations have I made you."⁹Genesis 17: 5. And our Rabbis explain: "In the past you were merely a father to Aram, but from now on [you are a father] of all nations.