Who Jesus (aka, The Word) is John 1:1-14
In the beginning was the Word, and the Word was with God, and the Word was God. He was with God in the beginning. Through him all things were made; without him nothing was made that has been made. In him was life, and that life was the light of all mankind. The light shines in the darkness, and the darkness has not overcome it. ...The true light that gives light to everyone was coming into the world. He was in the world, and though the world was made through him, the world did not recognize him. He came to that which was his own, but his own did not receive him. Yet to all who did receive him, to those who believed in his name, he gave the right to become children of God— children born not of natural descent, nor of human decision or a husband's will, but born of God. The Word became flesh and made his dwelling among us. We have seen his glory, the glory of the one and only Son, who came from the Father, full of grace and truth.
Jesus was prophesied many hundreds of years in advance. From ~700 BC the Jewish Prophet Isaiah wrote: (Isaiah 9:6-7)
For a child will be born to us, a son will be given to us; And the government will rest on His shoulders; And His name will be called Wonderful Counselor, Mighty God, Eternal Father, Prince of Peace. There will be no end to the increase of His government or of peace, On the throne of David and over his kingdom, To establish it and to uphold it with justice and righteousness From then on and forevermore. The zeal of the LORD of hosts will accomplish this.…