In one place in his books, Maimonides writes "The goy must not observe the Sabbath and study the Torah," while in another place he says "If a Noahide wants to observe additional commandments besides the seven basic ones of B'nei Noah, he receives a reward from Heaven, and we (the Jews) must support him in this." Many people quote the first of his statements, not knowing about the existence of the second one. Rav Uri Scherki (and the rabbinical council of the Brit Olam organization) explain this contradiction in Maimonides by saying that the goy and B'nei Noah are different halakhic concepts.