I was reading John 4 last night about Jesus' encounter at Jacob's well with the Samaritan woman from Sychar. When she wanted to know why He was asking her for a drink, Jesus responded, "If you knew the gift of God, and who it is who says to you, 'Give Me a drink,' you would have asked Him, and He would have given you living water." The woman needed to know two things: 1) What is God's gift? and 2) Who gives the gift?
Jesus by His very question implies to her that He is the Giver of the gift. He also refers to the gift as "living water." Jesus continues the conversation telling the woman that "whoever drinks of the water that I will give him shall never thirst; but the water that I will give him will become in him a well of water springing up to eternal life." God's gift to us is eternal life and the one who gives it is Jesus. The woman still didn't quite get all that Jesus was trying to tell her and she said to Him, "I know that Messiah is coming (He who is called Christ); when that One comes, He will declare all things to us." Jesus' response was pointed and clear, "I who speak to you am He."
At this, the woman returned to Sychar and told others about her encounter with Jesus the Messiah. Many from the town went out to see Him and believed. What did they believe? Just what Jesus had told the woman - that God's gift is eternal life and He is the Giver of that gift to those who believe.
John 6:47 ""Truly, truly, I say to you, he who believes in Me has eternal life."