The Gospel of John portrays John the Baptist from a slightly different perspective than the Synoptic Gospels. Considering that John's Gospel centres on the priesthood of the New Covenant, I believe the author wanted to make full use of the fact that John the Baptist was born into Aaron's lineage, which held the legitimate priesthood of the Old Covenant. 

As the Gospel of Matthew clearly states, Jesus was born of Joseph of the house of David as his earthly father—He was born into David's lineage. For this reason, I believe that regarding the priesthood of the New Covenant—even though Jesus Himself brought it into the world—a prophecy by John the Baptist, who was of a legitimate priestly lineage, was indispensable. Although Jesus was God, He lived as a man amidst such social perceptions of the time.

Furthermore, Jesus had to fulfil the words the angel had revealed to Mary: "He will be great, and will be called the Son of the Most High; and the Lord God will give to him the throne of his father David, and he will reign over the house of Jacob for ever" (Luke 1:32–33). 

After instituting the Eucharist, Jesus said: "You are those who have continued with me in my trials; and I assign to you, as my Father assigned to me, a kingdom" (22: 28–29), thereby ensuring that the authority of the Apostles he had chosen would be passed on. In this way, Jesus fulfilled the angel's words. 

Meanwhile, the priesthood of the New Covenant conferred upon the Apostles at the institution of the Eucharist through Jesus' words, "Do this in remembrance of me" (22:19), was hidden in their memory. This was so that, when the Apostles and their successors celebrate the scene of the institution of the Eucharist as a memorial after the descent of the Holy Spirit, sent in the name of Jesus (cf. John 14:26), the Holy Spirit might draw forth from their memory the words and actions of the priesthood of the New Covenant; and, in union with them, make the time of Jesus present and bring forth the Eucharist. 

John the Baptist prophesied these things, saying as follows:

"No one can receive anything except what is given him from heaven. You yourselves bear me witness, that I said, I am not the Christ, but I have been sent before him. He who has the bride is the bridegroom; the friend of the bridegroom, who stands and hears him, rejoices greatly at the bridegroom's voice; therefore this joy of mine is now full. He must increase, but I must decrease" (John 3:27–30). 

I believe this prophecy likens the Holy Spirit, who would be sent in the future in the name of Jesus, to the "bridegroom," and the priesthood of the New Covenant to the "bride." Just as John the Baptist was born into the legitimate lineage of the old covenant priesthood and received from heaven his role as the one "sent before him," so too do the Apostles and their successors receive the priesthood of the New Covenant from heaven, becoming those "sent before" the Holy Spirit, and bearing witness to the prophetic words of John the Baptist. 

A priest who keeps the priesthood of the New Covenant hidden in his memory is truly like a "friend" of the Holy Spirit, who draws words and actions from the priest's memory during the Mass to make the time of Jesus present and to bring forth the Eucharist. In the priest, we see one who hears the Holy Spirit’s voice in his own voice, becomes the hands and feet of the Holy Spirit, and works with a selfless heart. 

Priests who collaborate with the Holy Spirit seem to be living out John the Baptist's prophecy: "He must increase, but I must decrease." And I believe that, in doing so, they too are repeating the words: "therefore this joy of mine is now full." 

As "my church" (Matthew 16:18) of Jesus, who received the priesthood of the New Covenant, how should we, believers, live to preserve this treasure? 

Maria K.M.