1 John 3:10

In this These words, like -for this cause" (1 John 3:1) refer to what precedes rather than to what follows: but here what follows is similar to what precedes, so that in any case -in this" means -by doing or not doing righteousness".

are manifest A man's principles are invisible, but their results are visible: -By their fruits ye shall know them" (Matthew 7:16-20).

the children of the devil The expression occurs nowhere else in N. T., but we have -son of the devil," Acts 13:10: comp. -children of wrath" (Ephesians 2:3), and -ye are of your father the devil" (John 8:44). All mankind are God's children by creation: as regards this a creature can have no choice. But a creature endowed with free will can choose his own parent in the moral world. The Father offers him the -right to become a child of God" (John 1:12); but he can refuse this and become a child of the devil instead. There is no third alternative.

It was for pressing the doctrine that a tree is known by its fruits to an extreme, and maintaining that a world in which evil exists cannot be the work of a good God, that the heretic Marcion was rebuked by S. John's disciple Polycarp, in words which read like an adaptation of this text, "I know thee for the firstborn of Satan" (Iren. Haer.III. iii. 4). And in his Epistle (VII. 1) Polycarp writes, "Whosoever does not confess the witness of the cross is of the devil".

neither he that loveth not his brother Here again note the way in which S. John's divisions shade off into one another (see on 1 John 2:28-29). Doing righteousness, the mark of God's children, suggests the thought of brotherly love, for love is righteousness in relation to others;-For the whole law is fulfilled in one word, even in this; Thou shalt love thy neighbour as thyself" (Galatians 5:14). Love suggests its opposite, hate; and these two form the subject of the next paragraph. Some editors would make the new section begin here in the middle of 1 John 3:10. It is perhaps better to draw the line between 1 John 3:12, considering 1 John 3:11 as transitional.

-He that loveth not his brother is not of God", for a child of God will love all whom God loves. This prepares us for the statements in 1 John 4:7; 1 John 4:20-21.