I John 5:21

Affectionate parting caution. from idols--Christians were then everywhere surrounded by idolaters, with whom it was impossible to avoid intercourse. Hence the need of being on their guard against any even indirect compromise or act of communion with idolatry. Some at Pergamos, in the region whence John wrote, fell into the snare of eating things sacrificed to idols. The moment we cease to abide "in Him that is true (by abiding) in Jesus Christ," we become part of "the world that lieth in the wicked one," given up to spiritual, if not in all places literal, idolatry (Eph 5:5; Col 3:5). Next: 2 John Introduction

In this chapter the apostle asserts, I. The dignity of believers (Jo1 5:1). II. Their obligation to love, and the trial of it (Jo1 5:1-3). III. Their victory (Jo1 5:4, Jo1 5:5). IV. The credibility and confirmation of their faith (Jo1 5:6-10). V. The advantage of their faith in eternal life (Jo1 5:11-13). VI. The audience of their prayers, unless for those who have sinned unto death (Jo1 5:14-17). VII. The preservation from sin and Satan (Jo1 5:18). VIII. Their happy distinction from the world (Jo1 5:19). IX. Their true knowledge of God (Jo1 5:20), upon which they must depart from idols (Jo1 5:21).

5:21 In closing, John exhorts his flock to keep away from anything that might take God’s place in your hearts (literally keep yourselves from idols). In the context of 1 John, the primary idol would be any false teaching that takes people away from Jesus Christ, who is at once fully man and fully God.