Exodus 19:22 - Matthew Poole's English Annotations on the Holy Bible

For though the Aaronical priesthood was not yet appointed, it is certain, that as there were sacrifices before, so there were priests to offer them, which were either the first-born, who were consecrated to God, and did execute the office of priests, as may be gathered from Exodus 13:2, Exodus 24:5 Numbers 3:12, Numbers 8:26, or some other persons appointed by God for doing that work till the office was settled in Aaron's family. Which come near to the Lord; not at this time, for both priests and people are now kept at equal distance, Exodus 19:24; but usually: q.d. Whose duty and privilege it is to approach unto God, and to present the people's prayers and sacrifices to him, and therefore are here particularly admonished, because they above all others are obliged to this care, and because they might seem to claim this privilege by their function.