Up to the time of St. John the Baptist's first appearance, the sons and daughters of Abraham were the chosen people of God by virtue of their ethnic heritage and religious affiliation. But all that would change with the New Covenant Church.
As Jesus himself would later say, “The hour is coming, and is now here, when true worshipers will worship the Father in Spirit and truth; and indeed the Father seeks such people to worship him. God is Spirit, and those who worship him must worship in Spirit and truth.” Worshiping in Spirit and truth would necessitate faith, love, and repentance from sin. The message was clear: Being a descendant of Abraham was not enough. One would have to be an imitator of Abraham in the Spirit. This would be the seal of those who belonged to God’s new family.
Although the New Covenant religion would receive its life from the Spirit, it did not dispense from rituals and sacrifice as such. Indeed, a new priesthood and a clean sacrifice would be inaugurated with the coming of the Messiah. As the prophet Malachi foretold in the Old Testament, “For from the rising of the sun, even to its setting, my name is great among the nations; And everywhere they bring sacrifice to my name, and a pure offering; for great is my name among the nations, says the LORD of hosts.” And St. John, the son of Zechariah, and a descendant of Levi, would point out the New High Priest and the Lamb of God for all to see. In fact, in the Gospel of John the Baptist said, “Behold, the Lamb of God, who takes away the sin of the world!” And upon this Lamb, he “saw the Spirit come down like a dove from heaven and remain upon him.” Indeed, the preaching of St. John the Baptist helped ushered in a new High Priest, a new sacrifice, and a new priesthood.
With the decent of the Holy Spirit, God the Father would speak his blessing upon the Son of Man. Heaven would, after thousands of years, open its doors again to mankind: "After Jesus was baptized, he came up from the water and behold, the heavens were opened for him and he saw the Spirit of God descending like a dove and coming upon him. And a voice came from the heavens, saying, 'This is my beloved Son, with whom I am well pleased.'"
“The heavens were opened for him.” The importance of these words cannot be overstated. Just before God “baptized” the world with a global flood, he assessed the sinfulness of mankind and “regretted that he had made man on the earth, and his heart was grieved.” The Lord then promised to do something which would prove more devastating than the flood itself. He said, "My spirit shall not remain in man forever, since he is but flesh." As if to say, “Okay. You don’t want me, I will leave you at the mercy of your own devices.” So, God went up to heaven, thus taking his Spirit, and the doors of heaven were closed to man. From the days of Noah to Pentecost, humanity did not benefit from the presence of Holy Spirit. As such, each person was at the mercy of his weak human nature. And as one peruses the pages of the Old Testament and the books of ancient history, one cannot help but notice the barbarity and cruelty of man; even among God’s chosen people. Such was the world without the Holy Spirit.
From about 500 B.C. to the time St. John the Baptist raised his voice in the desert, the voices of prophets were silenced. In other words, for about four to five hundred years leading up to the time of Christ, God had not sent any prophets to the Jews. Which prophet broke that silence? St. John the Baptist!
What is more, when he baptized the Son of God in the river Jordan, God the Father himself finally spoke again: “This is my beloved Son, with whom I am well pleased.” The doors of heaven were opened and God the Father sent out his Dove in order to find a resting place (much like Noah sending a dove from the ark in order to find dry land). His Spirit, which had been withdrawn from the world in Genesis chapter 6, once again descended to earth and rested on his Son. Perhaps, this is why St. John said, “I saw the Spirit come down like a dove from heaven and remain upon him.” In other words, the Spirit of God who had appeared in the form of a dove did not go back up to heaven; he was here to stay!
The public declaration of the Father’s love for the Son was accompanied by the anointing of the Spirit. Jesus would later say of himself in the synagogue: “The spirit of the Lord GOD is upon me, because the LORD has anointed me.” These words from the prophet Isaiah signify a kind of consecration or priestly ordination. The words of paternal affection with which the Father spoke to his Son in the Gospel of Matthew finds its parallel from Psalm 110 in which he also says, “In holy splendor before the daystar, like the dew I begot you. The LORD has sworn and will not waver: Like Melchizedek you are a priest forever."
In the river Jordan, St. John, the son of Zechariah the priest, baptized the Son of God. But this was not just a baptism of water. No. This was a kind of ordination from the eternal Father to his Son. Perhaps, this is why St. John could proclaim: “Behold, the Lamb of God, who takes away the sin of the world.” Christ, as we have seen, is not only the Lamb to be sacrificed but a priest according to the order of Melchizedek.
“It is even more obvious if another priest is raised up after the likeness of Melchizedek, who has become so, not by a law expressed in a commandment concerning physical descent but by the power of a life that cannot be destroyed.” (Hebrews 7) At the river Jordan a new priesthood was inaugurated through which “the power of life” would be communicated to the world. This priesthood is to be found in the Catholic Church. And to be sure, it is the reason why the Catholic priesthood is the hope of nations.