3:10 The absence or presence of sin in the believer's life gives evidence of his or her relationship to God and Satan. It shows under whose authority we are living. John divided the world into two classes: those whose parentage is either divine or diabolical.
"The key word here is manifest.' A sinning Christian concealshis true character when he sins and revealsit only through holiness. On the other hand, a child of Satan revealshis true character by sin."129
Christians can and do identify other Christians by their righteous behavior. This is not the same as saying every true Christian without exception will produce good works (cf. John 15:1-8). Christians who are abiding in God will produce good works, and others can identify them as Christians by their godly behavior. The sinless behavior produced and perceived is a manifestation of God's love (v. 1).
The absence of righteous behavior in a life indicates the absence of intimacy with God. Likewise the absence of love for one's brother Christian shows that the individual who does not love has little fellowship with God. Love is the most important particular manifestation of righteous behavior. John proceeded to discuss this trait more fully.
"The whole aim of the Gospel is the creation and strengthening of love.130
3:11 The message that John and his faithful followers had heard from the beginning was Jesus' command to His disciples to love one another as He had loved them (John 13:34-35; 15:12).
