The text I find with the word "race" is when explaining that the nazis are defining Jews as a race. I cant seem but to find the idea of defining a race as "any

The text I find with the word "race" is when explaining that the nazis are defining Jews as a race. I cant seem but to find the idea of defining a race as "anyone belonging to this religion" so incomprehensible that I probably can't read the text the way it's supposed to be read. Does that mean that simply being born to a Jewish father makes you a part of the Jewish race? Does it then mean that by rejecting your religion, your race changes? I guess I really have no idea what race means.