1 John 2:3

hereby we do know that we know Him Or, herein we come to know that we know Him: in the Greek we have the present and perfect of the verb which means -to come to know, perceive, recognise" (γινώσκειν); the perfect of which, -I have come to know" = -I know." Comp. the Collect for the First Sunday after Epiphany; -that they may both perceive and knowwhat things they ought to do." Progressive knowledge gained by experience is implied. -Herein" followed by -if", or -that", or -because", or -when, is a frequent construction in S. John: John 2:5; John 3:16; John 3:19; John 4:9-10; John 4:13; John 4:17; John 5:2; John 13:35; John 15:8. Excepting Luke 10:20, it occurs nowhere else in N. T.

if we keep His commandments This is equivalent to -not sinning" in 1 John 2:1, and to -walking in the light" in 1 John 1:6. There is no real knowledge of God, no fellowship with Him, without practical conformity to His will. Nam quisquis eum non amat, profecto ostendit, quia quam sit amabilis, non novit(Bede). S. John is again condemning that Gnostic doctrine which made excellence to consist in mere intellectual enlightenment. Divorced from holiness of life, says S. John, no enlightenment can be a knowledge of God. In his system of Christian Ethics the Apostle insists no less than Aristotle, that in morals knowledge without practice is worthless: -not speculation but conduct" is the aim of both the Christian and the heathen philosopher. Mere knowledge will not do: nor will knowledge -touched by emotion" do. It is possible to know, and admire, and in a sort of way love, and yet act as if we had not known. But S. John gives no encouragement to devotion without a moral life(comp. 1 John 1:6). There is only one way of proving to ourselves that we know God, and that is by loving obedience to His will. Compare the very high standard of virtue set by Aristotle: he only is a virtuous man who does virtuous acts, "first, knowingly; secondly, from deliberate preference, and deliberate preference for the sake of the acts (and not any advantages resulting from them); and thirdly, with firm and unvarying purpose" (Nic. Eth.II. iv. 3).

The phrase -to keep (His) commandments" or -keep (His) word" is of frequent occurrence in S. John's writings, Gospel (John 14:15; John 14:21; John 15:10; John 8:51-52; John 8:55; John 14:23; John 15:20; John 17:6), Epistle (1Jn 2:4, 1 John 3:22; 1Jn 3:24; 1 John 3:5:[2,] 3; 1 John 2:5) and Revelation (Revelation 12:17; Revelation 14:12; Revelation 3:8; Revelation 3:10). Comp. John 14:24; Revelation 22:7; Revelation 22:9. The word -to keep" (τηρεῖν) means to be on the watch to obey and fulfil; it covers both outward and inward observance.