And this is life eternal. — For these words, which are more frequent in St. John than in any other of the New Testament writers, comp. John 3:15-16; John 3:36; John 5:24; John 5:39; John 6:27; John 6:40; John 6:47; John 6:54; John 6:68; John 10:28; John 12:25; John 12:50; 1 John 1:2; 1 John 2:15; 1 John 3:15; 1 John 5:11; 1 John 5:13; 1 John 5:20. The thought of the previous verse is that the Messianic work of Christ is to give eternal life to those whom God has given Him. The thought of the following verse is that He has accomplished this work. In this verse He shows in what its accomplishment consists — viz., in revealing to men the only true God through Jesus Christ.
That they might know thee the only true God. — Better, That they might recognise Thee as the only true God. (Comp. Notes on John 1:9; John 14:7.)
And Jesus Christ, whom thou hast sent. — Better, And Him, whom Thou didst send, Jesus, as Messiah. Eternal life consists in the knowledge of the Father as the only Being answering to the ideal thought of God; and in this knowledge manifested in Him, whom God anointed and sent into the world-to declare His attributes and character. Only in the Word made flesh can we hear the voice of mercy, forgiveness, love, fatherhood; which comes to men as the breath of life, so that they become living souls.