R. Yehudah says: The verse is to be taken literally (i.e., to the gentile, by selling, and not as a gift, to the ger, as a gift, and not by selling.)
"for a holy people are you to the L-rd your G-d": Sanctify yourself with what is permitted to you, viz.: That which is permitted and others forbid to themselves (as a special act of piety), you are forbidden to permit to yourselves in their presence.
"You shall not cook a kid in the milk of its mother": Why is this written three times? To exclude (from this prohibition) an animal, a bird, and an unclean beast.