It is true that “the whole world lies in the power of the evil one” (v19b). John, of course, does not deny God’s sovereignty by making this statement. Rather, he is making a sharp distinction: we are from God whereas the world places itself under Satan’s dominion. This truth remind us of many things when all seems hopeless: 1. The world (that is, unbelievers) believes lies, sins, and hates truth because it is the world, 2. Sinners do what they do because they are under satanic power and need to be rescued, 3. We are citizens of an entirely different kingdom, with a different King, and therefore we behave differently, and 4. God is greater than the wicked one and will be vindicated.
When the actions and proclamations of the world discourage you, remember two basic truths: 1. Consider who the world is and 2. Consider who we are – we belong to God!