The Gospel of Saint John was written by John the Apostle also known as John the Evangelist who also wrote the Book of Revelation. He was known as the beloved eye witness of Jesus. For an overview of this Gospel, please read the link at http://www.newadvent.org/cathen/08438a.htm
Some call this Gospel the mystical Gospel because there is a depth of spirituality that distinguishes it from the other Gospels. It is also called the Sacramental Gospel because if you look into the Gospel of John, you will find the foundational statements for each of the seven Sacraments.
1. John Chapter 1 tells of Baptism,
2. John Chapter 8 verse 11 and Chapter 20 verse 23 tells of sacramental confession,
3. John Chapter 6 verses 51-59 tells of the Eucharist, the source and summit of our lives,
4. John Chapter 14 verses 26-27 and Chapter 16 verses 13-14 tells of Confirmation,
5. John Chapter 2 tells of Matrimony when Jesus ministers to the people at the wedding in Cana
6. John Chapter 21 verses 15-19 tells of Holy Orders
7. John Chapter 9 and others tell of the anointing of the sick
The first part of the Gospel of Saint John or prologue is so mighty that it will be today's post.
259. John 1: 1-18 In the beginning was the Word, and Word was with God, and the Word was God. He was in the beginning with God. All things came to be through Him and without Him nothing came to be. What came to be through Him was life, and this life was the light of the human race; the light shines in the darkness, and the darkness has not overcome it. A man named John was sent from God. He came for testimony, to testify to the light, so that all might believe through him. He was not the light, but came to testify to the light. The true light, which enlightens everyone, was coming into the world.
He was in the world, and the world came to be through Him, but the world did not know Him. He came to what was His own, but His own people did not accept Him. But to those who did accept Him He gave power to become children of God, to those who believe in HIS NAME, who were born not by natural generation nor by human choice nor by a man's decision but of God.
And the Word became flesh and made His dwelling among us, and we saw His glory, the glory as of the Father's only Son, full of grace and truth.
John testified to Him and cried out, saying, "This was He of Whom I said, 'The One Who is coming after me ranks ahead of me because He existed before me.'" From His fullness we have all received, grace in place of grace, because while the law was given through Moses, grace and truth came through Jesus Christ. No one has ever seen God. The only Son, God, Who is at the Father's side, has revealed Him.