51 Accordingly, the Son came to the servant; not that the Son might be presented by the servant, but that by the Son the servant might present to His Lord Priesthood and Prophecy, to be laid up with Him. For prophecy and priesthood, which were given through Moses, were handed down, both of them, and reached to Simeon. For he was a pure vessel, who sanctified himself that he might be like Moses, capable for both of them. There are small vessels which are capable for great gifts.
There are gifts for which one is capable, by reason of their grace; yet many are not capable for them, by reason of their greatness. Thus, then, Simeon presented our Lord, and in Him offered both these things; so that that which was given to Moses in the wilderness, was received from Simeon in the Temple. But seeing that our Lord is the vessel wherein all fullness dwells, when Simeon was offering Him before God, he poured over Him (as a drink-offering) those two (gifts), priesthood from His hands and prophecy from His lips.
Priesthood continued on the hands of Simeon, because of his purifications; and prophecy dwelt in operation upon his lips, because of revelations. When then these two powers saw Him who was Lord of both, they two united together and poured themselves into the vessel that was capable of both; that could contain priesthood and kingdom and prophecy. That Infant then, who was wrapped in swaddling clothes, because of His graciousness, clothed Himself in priesthood and prophecy because of His Majesty.
For Simeon clothed Him in these, and gave Him to her who had wrapped Him in swaddling clothes. For when he gave Him to His mother, he gave along with Him the priesthood; and when he prophesied to her concerning Him, This (child) is set for the fall and rising again, he gave prophecy also with Him.
Source: On Our Lord (New Advent)