<p>3:13- see on Jn. 5:28.</p><p><em>Marvel not brothers if the world hates you</em>- As explained on :12, it is the unconscious exposure of others' sin by our example which will lead to hatred. The Jewish converts were apparently surprised that the Jewish religious world would hate them. John is explaining that such hatred is completely to be expected. But in this very context, John warns about <em>some brethren</em> who hate their brethren, and who thereby abide in darkness (1 Jn. 3:15; 4:20). John's simple logic is evident: if you hate your brother, you're in the world, you've put yourself into darkness, you've condemned yourself. The place of the rejected believers is in the ranks of the world- nowhere else.</p>