Albert Barnes Commentary 1 John 5:19

"We know that we are of God, and the whole world lieth in the evil one." — 1 John 5:19 (ASV)

And we know that we are of God. We who are Christians. The apostle supposed that true Christians might have such clear evidence on that subject as to leave no doubt on their own minds that they were the children of God. Compare to 1 John 3:14; 2 Timothy 1:12.

And the whole world. The term world here evidently means not the material world, but the people that live on the earth, including all idolaters, and all sinners of every grade and kind.

Lies in wickedness. "In the wicked one," or under the power of the wicked one—en tō ponērō. It is true that the word ponērō may be used here in the neuter gender, as our translators have rendered it, meaning "in that which is evil," or in "wickedness;" but it may be in the masculine gender, meaning "the wicked one;" and then the sense would be that the whole world is under his control or dominion. That this is the meaning of the apostle seems to be clear, because:

1. The corresponding phrase (1 John 5:20) en tō alēthinō, "in him that is true," is evidently to be construed in the masculine, referring to God the Savior, and meaning "him that is true," and not that we are "in truth."
2. It makes better sense to say that the world lies under the control of the wicked one, than to say that it lies "in wickedness."
3. This accords better with the other representations in the Bible, and the usage of the word elsewhere. Compare to 1 John 2:13, You have overcome the wicked one; 1 John 5:14, you have overcome the wicked one; 1 John 3:12, who was of that wicked one. See Barnes' notes on 2 Corinthians 4:4, on the expression the god of this world;John 12:31, where he is called the prince of world; and Ephesians 2:2, where he is called the prince of the power of the air. In all these passages it is supposed that Satan has control over the world, especially the heathen world. Compare to Ephesians 6:12; 1 Corinthians 10:20. In regard to the fact that the heathen world was pervaded by wickedness, see Barnes' notes on Romans 1:21 and following.
4. It may be added, that this interpretation is adopted by the most eminent critics and commentators. It is that of Calvin, Beza, Benson, Blacknight, Bloomfield, Piscator, Lucke, etc. The word lies here (keitai) means, properly, to lie; to be laid; to recline; to be situated, etc. It seems here to refer to the passive and torpid state of a wicked world under the dominion of the prince of evil, as acquiescing in his reign; making no resistance; not even struggling to be free.

It lies thus like a beast that is subdued, a body that is dead, or anything that is wholly passive, quiet, and inert. There is no energy; no effort to throw off the reign; no resistance; no struggling. The dominion is complete, and body and soul, individuals and nations, are entirely subject to his will.

This striking expression will aptly describe, even now, the condition of the heathen world, or of sinners in general. There would seem to be no government under which people are so little restive, and against which they have so little disposition to rebel, as that of Satan. Compare to 2 Timothy 2:26.