The next law that G‑d taught the Jewish people was the requirement to separate a portion of their dough and give it to the priests.
Authority
קַח אֶת הַלְוִיִּם תַּחַת כָּל בְּכוֹר בִּבְנֵי יִשְׂרָאֵל וגו': (במדבר טו:כ)
[G‑d instructed Moses to tell the Jewish people,] “[Of] the first of your dough, donate a loaf [to a priest].” Numbers 15:20

The Torah grants the privileges and responsibilities of the priests only to the descendants of Aaron. To be sure, all Jews are of equal inherent value and equally deserve our love and respect. However, when dealing with the question of who can be a religious practitioner or authority – whether a priest or a rabbi – we must realize that G‑d has determined who can and who cannot assume these titles. Just as priests can only be descendants of Aaron, rabbis and teachers can only be individuals who have attained the necessary levels of knowledge, who are truly G‑d-fearing, who observe all the dictates of the Torah, and who have absorbed the traditions transmitted through the generations.

Just as we require strict qualifications for those entrusted with guiding and facilitating our external religious lives, we should equally require strict qualifications for those inner voices that purport to tell us how to behave. We should constantly question our inner voices, in order to be sure that we are being guided only by pure and positive motives.1