Bottom line: Believe Jesus and you will have life eternally. Know Jesus more and more and you will experience life abundantly.

John wrote his gospel to convince his readers that Jesus was the Son of God and that by believing, they would have eternal life. If we believe, we are saved. And if saved, we need to get to know the One that saved us. He is the Word, the Creator, the Light of Life, the Son of God, the Lamb of God, and the Messiah. The more you know Him, the more abundant your life will be.
We are the stewards of the message of life. We are the stewards of the message of a better life. The more you know Jesus, the better (sweeter experience) life is.