"And this is life eternal, that they might know thee, the only true God and Jesus Christ whom thou hast sent" (Jn 17.3). I have always been attracted to this passage for some unknown reason. One cannot argue that it is even the burden of the passage (vv1-5). Rather, it is explanatory as C. K. Barrett says of the 'eternal life' mentioned in verse 2.
It is also a text that is a battleground between Trinitarian and non-Trinitarian views with some arguing that Jesus Christ cannot be God because Jesus says that the Father is the 'only true God'. However, this position avoids the embarrassment found in considering that eternal life is found in knowledge of God the Father and in Jesus Christ. The simple but powerfully evocative bracketting of the two speaks volumes re the status of the Son (quite apart from many other passages of scripture).
Knowledge of the Father and the Son is eternal life; in this, St John is stating what every Jew knew about God. To acknowledge or know (so the literal sense according to Barrett) God is to experience his direction of one's paths (Prov 3.6).
In St John chapter 20 (v31), believing is related to life through his (Christ's) name. Barrett ties believing and knowing together by saying that they are not to be pitted against each other but are to be understood as correlated.
Eternal life is equated with knowing the only true God and his apostle, Jesus Christ, and that knowledge is experiential, personal and intimate brought about by the Holy Spirit enlightening the eyes of the understanding captured by obedience to his word.
