The Importance of ‘knowing’ truth
I. Truth sets us free from sin.
See John 8:31-32.
31 To the Jews who had believed him, Jesus said, ‘If you hold to my teaching, you are really my disciples. 32 Then you will know the truth, and the truth will set you free.’
This freedom is freedom from slavery to sin (John 8:34-36). The Condition of becoming ‘to know the truth’ is ‘if you hold to my teaching’.
II. ‘knowing’ God and Jesus Christ is ‘eternal life’
See John 17:3.
3 Now this is eternal life: that they know you, the only true God, and Jesus Christ, whom you have sent.
Knowledge
“The word know in verse 3 is ginosko, emphasizing an experiential relationship rather than just necessary information. The verb also appears here in the present tense, suggesting a continuing personal experience and contact with both the Father and the Son.” [2].
“In Judaism, the knowledge of God is primarily the revelation of God contained in his Law, and obedience to this Law means life. That is, true knowledge of God was tied to a particular historical revelation, and this knowledge demanded faith and obedience. The same belief is reflected in the Gospel of John. The knowledge of God referred to here is the knowledge which comes through a specific revelation in Jesus Christ, and it demands a response of love and obedience on the part of those who follow. Knowledge, then, for both Old Testament and New Testament writers is not a beatific vision or an intuitive feeling about God; rather it is based on an objective revelation and demands a positive response in obedience and love.” [4]
Eternal Life
“Christ’s definition of eternal life is important because it differs from the current concept of endless existence” [2].
"Tenney [3] writes, “However fully man lives in the world, he ultimately reaches the point where nothing is new because he has reached human limits. Only the knowledge of God can give enduring satisfaction, because God alone is eternal. Contact with God will provide the fullest experience, and the experience of God’s eternal being will be eternal life”." [2]
References
[1] The Holy Bible: New International Version (Anglicised Edition, 2011). (2011). (Revised and updated edition). London: Hodder & Stoughton.
[2] Gangel, K. O. (2000). John (Vol. 4, p. 313). Nashville, TN: Broadman & Holman Publishers.
[3] Tenney, Merrill C. John: The Gospel of Belief (pp. 245–46). Cambridge: William B. Eerdmans Publishing Company.
[4] Newman, B. M., & Nida, E. A. (1993). A handbook on the Gospel of John (p. 527). New York: United Bible Societies.