They Know the Father and the Eternal Word and Must Beware of Loving The World (1 John 2:12-17).
Having exhorted them of the need to remain true to Him and to the Word Who ‘is' from the beginning, and to love those who are true to Christ, he now rejoices in the fact that they are of those who have been forgiven and know both Father and Son. This contrasts with the false teachers who denied the need for forgiveness and sought to introduce lesser lights and to diminish the Son. (Heresy regularly seeks to diminish the importance of sin and the status of the Son, blurring the clear Biblical distinctions). Then he warns his readers of the danger of loving ‘the world'. This refers not to the world of men (as in John 3:16) but to the attractions and allurements and ways of the world which can only lead them away from God and thus lead them astray. The church, which was now established, faced enemies both within and without. He has dealt with the question of those within (and will again do so later) but now he turns his thoughts on the enemies without.
There is a problem here as to how we are to connect the opening verses. Are we to take 1 John 2:12 as introductory, seeing it then as expanded in 1 John 2:13 a dividing the ‘little children' into fathers and young men, (compare ‘young men -- old men' in Joel 2:28-29), followed again by a similar pattern in the second series, thus giving three ‘I write' and three ‘I have written' phrases which are parallel? Or are we to see a reference to babes in Christ either in terms of teknia and paidia, (or of paidia alone with teknia referring to all), with separate references to fathers and young men, so that in mind are babes, fathers and young men? For gaining the sense it is not really important. In the commentary we work on the basis of the first interpretation due to the otherwise strange order of ‘babes, fathers and young men'. On the other hand it may be that the young men are deliberately placed last because they are the most likely to be affected by the attractions of the world which are then spoken of.