My interest was in finding out how much John the Baptist and John the Apostle concentrated on the relationship within the Holy Trinity. Most folks concentrate on John the Baptists ministry preparing the way and calling folks to repentance. But John the Baptist's beliefs in John 3 is remarkably exact with the rest of the chapter. Especially on "has Eternal Life". (verse 36).
The Doctrine is precise and exquisite.
Nativity of John the Baptist - 1523 - Rome
from The Book of Gospels, Midwest Theological Forum (see links page)
Nativity of Saint John the Baptist: Born six months before our Lord, Saint John the Baptist was the son of Zechariah and Elizabeth, our Lady's couin. He was the last and greatest of the prophets. As the forerunner of the Savior, he had the mission of preparing the Jews for the coming of Christ. When Jesus had come, Saint John bore witness to Him before his own followers and encouraged them to follow Him.
Source: Daily Roman Missal, Edited by Rev. James Socías, Midwest Theological Forum, Chicago, Illinois ©2003
Readings for the Birth of Saint John the Baptist
All powerful God,
help Your people to walk the path to salvation.
By following the teaching of St. John the Baptist,
may we come to your Son, our Lord Jesus Christ,
who lives and reigns with You and the Holy Spirit,
one God, for ever and ever. + Amen.
First Reading: Isaiah 49:1-6
Listen to me, O coastlands, and hearken, you peoples from afar. The Lord called me from the womb, from the body of my mother He named my name. He made my mouth like a sharp sword, in the shadow of His hand He hid me; He made me a polished arrow, in His quiver He hid me away. And He said to me, "You are My servant, Israel, in whom I will be glorified." But I said, "I have labored in vain, I have spent my strength for nothing and vanity; yet surely my right is with the Lord, and my recompense with my God."
And now the Lord says, who formed me from the womb to be His servant, to bring Jacob back to Him, and that Israel might be gathered to Him, for I am honored in the eyes of the Lord, and my God has become my strength-- He says: "It is too light a thing that you should be My servant to raise up the tribes of Jacob and to restore the preserved of Israel; I will give you as a light to the nations, that My salvation may reach to the end of the earth."
Second Reading: Acts 13:22-26
In those days, Paul said, God raised up David to be their king; of whom He testified and said, 'I have found in David the son of Jesse a man after My heart, who will do all My will.' Of this man's posterity God has brought to Israel a Savior, Jesus, as He promised. Before His coming John had preached a baptism of repentance to all the people of Israel. And as John was finishing his course, he said, 'What do you suppose that I am? I am not He. No, but after me one is coming, the sandals of whose feet I am not worthy to untie.'
"Brethren, sons of the family of Abraham, and those among you that fear God, to us has been sent the message of this salvation.
Gospel Reading: Luke 1:57-66, 80
Now the time came for Elizabeth to be delivered, and she gave birth to a son. And her neighbors and kinsfolk heard that the Lord had shown great mercy to her, and they rejoiced with her. And on the eighth day they came to circumcise the child; and they would have named him Zechariah after his father, but his mother said, "Not so; he shall be called John." And they said to her, "None of your kindred is called by this name." And they made signs to his father, inquiring what he would have him called. And he asked for a writing tablet, and wrote, "His name is John." And they all marveled. And immediately his mouth was opened and his tongue loosed, and he spoke, blessing God. And fear came on all their neighbors. And all these things were talked about through all the hill country of Judea; and all who heard them laid them up in their hearts, saying, "What then will this child be?" For the hand of the Lord was with him.
And the child grew and became strong in spirit, and he was in the wilderness till the day of his manifestation to Israel.
Vigil Mass Readings for the Birth of Saint John the Baptist
First Reading: Jeremiah 1:4-10
'Now the word of the Lord came to me saying, "Before I formed you in the womb I knew you, and before you were born I consecrated you; I appointed you a prophet to the nations." Then I said, "Ah, Lord God! Behold, I do not know how to speak, for I am only a youth." But the Lord said to me, "Do not say, 'I am only a youth'; for to all to whom I send you you shall go, and whatever I command you you shall speak. Be not afraid of them, for I am with you to deliver you, says the Lord." Then the Lord put forth His hand and touched my mouth; and the Lord said to me, "Behold, I have put My words in your mouth. See, I have set you this day over nations and over kingdoms, to pluck up and to break down, to destroy and to overthrow, to build and to plant."
Second Reading: 1 Peter 1:8-12
Without having seen Him you love Him; though you do not now see Him you believe in Him and rejoice with unutterable and exalted joy. As the outcome of your faith you obtain the salvation of your souls.
The prophets who prophesied of the grace that was to be yours searched and inquired about this salvation; they inquired what person or time was indicated by the Spirit of Christ within them when predicting the sufferings of Christ and the subsequent glory. It was revealed to them that they were serving not themselves but you, in the things which have now been announced to you by those who preached the good news to you through the Holy Spirit sent from heaven, things into which angels long to look.
Gospel Reading: Luke 1:5-17
In the days of Herod, king of Judea, there was a priest named Zechariah, of the division of Abijah; and he had a wife of the daughters of Aaron, and her name was Elizabeth. And they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless. But they had no child, because Elizabeth was barren, and both were advanced in years.
Now while he was serving as priest before God when his division was on duty, according to the custom of the priesthood, it fell to him by lot to enter the temple of the Lord and burn incense. And the whole multitude of the people were praying outside at the hour of incense. And there appeared to him an angel of the Lord standing on the right side of the altar of incense. And Zechariah was troubled when he saw him, and fear fell upon him. But the angel said to him, "Do not be afraid, Zechariah, for your prayer is heard, and your wife Elizabeth will bear you a son, and you shall call his name John. And you will have joy and gladness, and many will rejoice at his birth; for he will be great before the Lord, and he shall drink no wine nor strong drink, and he will be filled with the Holy Spirit, even from his mother's womb. And he will turn many of the sons of Israel to the Lord their God, and he will go before him in the spirit and power of Elijah, to turn the hearts of the fathers to the children, and the disobedient to the wisdom of the just, to make ready for the Lord a people prepared."