I knew.

John 1:33
I myself did not know Him, but the One who sent me to baptize with water told me, 'The man on whom you see the Spirit descend and rest is He who will baptize with the Holy Spirit.'

Luke 1:80
And the child grew and became strong in spirit; and he lived in the wilderness until the time of his public appearance to Israel.

Luke 2:39-42
When Jesus' parents had done everything required by the Law of the Lord, they returned to Galilee, to their own town of Nazareth. . . .

but.

John 1:7
He came as a witness to testify about the Light, so that through him everyone might believe.

Isaiah 40:3-5
A voice of one calling: "Prepare the way for the LORD in the wilderness; make a straight highway for our God in the desert. . . .

Malachi 3:1
"Behold, I will send My messenger, who will prepare the way before Me. Then the Lord whom you seek will suddenly come to His temple--the Messenger of the covenant, in whom you delight--see, He is coming, " says the LORD of Hosts.

Malachi 4:2-5
"But for you who fear My name, the sun of righteousness will rise with healing in its wings, and you will go out and leap like calves from the stall. . . .

Luke 1:17, 76-79
And he will go on before the Lord in the spirit and power of Elijah, to turn the hearts of the fathers to their children, and the disobedient to the wisdom of the righteous--to make ready a people prepared for the Lord." . . .

therefore.

Matthew 3:6
Confessing their sins, they were baptized by him in the Jordan River.

Mark 1:3-5
"A voice of one calling in the wilderness, 'Prepare the way for the Lord, make straight paths for Him.'" . . .

Luke 3:3, 4
He went into all the region around the Jordan, proclaiming a baptism of repentance for the forgiveness of sins, . . .

Acts 19:4
Paul explained: "John's baptism was a baptism of repentance. He told the people to believe in the One coming after him, that is, in Jesus."