Aaron was chosen by God to be the first High Priest of the Old Law. Aaron was the brother of Moses and Miriam. He belonged to the tribe of Levi, the clerical (Levitical) tribe of the Jews. Aaron lived fourteen hundred years before the coming of Christ. Aaron was the ancestor in blood and in priestly lineage of Saint Zachary, the father of Saint John the Baptist. Saint Elizabeth, the mother of Saint John the Baptist — who gave us the second invocation in the Hail Mary, “Blessed art thou among women and blessed is the fruit of thy womb” — was, as we are told in the Gospel of Saint Luke, “one of the daughters of Aaron.”
Aaron died, and was buried on a mountain (Mount Hor) just outside the Promised Land. Aaron as a priest was a type of what Jesus was to be. That is why he is honored among the saints. Jesus is the sole High Priest of the New Law. He gave us His Precious Blood in sacrifice at the Last Supper. And in the Sacrament of Holy Orders, administered by Catholic bishops — the successors of the Apostles — Jesus has given us the true priesthood of our day. Aaron’s priesthood perished on the first Good Friday with the rending of the veil of the Temple of Jerusalem. In the year 70 A.D., with the total destruction of the Temple, Aaron’s credentials were no more.