In order to mark out His people as dwelling before Him in holiness, He required of them complete purity and didn’t allow them to come before Him when defiled, even by involuntary or secret impurities. And when one considers that God was training a people to live in His presence, it becomes apparent that these rules for the maintenance of personal purity, pointing to the necessity of purity in the heart, were neither too stringent nor too minute.
by John MacArthur in the
MarArthur Study Bible, p 176