Watchman Nee has written the best explanation of what the New Testament means by “the world.” He notes,
(1) When we turn from the classics to the New Testament writers we find that their uses of kosmos fall into three main groups. It is used first with the sense of the material universe, the round world, this earth. For example, Acts 17:14, “the God that made the world and all things therein”; Matt. 13:35 (and elsewhere), “the foundation of the world”; John 1:10, “he was in the world, and the world was made by him”; Mark 16:15, “Go ye into all the world.”
(2) The second usage of kosmos is twofold. It is used (a) for the inhabitants of the world in such phrases as John 1:10, “the world knew him not”; 3:16, “God so loved the world”; 12:19, “the world is gone after him”; 17:21, “that the world may believe.” (b) An extension of this usage leads to the idea of the whole race of men alienated from God and thus hostile to the cause of Christ. For instance, Heb. 11:38, “Of whom the world was not worthy”; John 14:17, “whom the world cannot receive”; 14:27, “not as the world giveth, give I unto you”; 15:18, “If the world hateth you …”
(3) In the third place we find kosmos is used in Scripture for worldly affairs: the whole circle of worldly goods, endowments, riches, advantages, pleasures, which though hollow and fleeting, stir our desire and seduce us from God, so that they are obstacles to the cause of Christ. Examples are: 1 John 2:15, “the things that are in the world”; 3:17, “the world’s goods”; Matt. 16:26, “if he shall gain the whole world, and forfeit his life”; 1 Cor. 7:31, “those that use the world, as not abusing it.” This usage of cosmos applies not only to material but also to abstract things which have spiritual and moral (or immoral) values. E.g., 1 Cor. 2:12, “the spirit of the world”; 3:19, “the wisdom of this world”; 7:31, “the fashion of this world”; Titus 2:12, “worldly (adj, kosmikos) lusts”; 2 Pet. 1:4, “the corruption that is in the world”; 2:20, “the defilement’s of the world”; 1 John 2:16, 17, “all that is in the world, the lust … the vainglory … passeth away.” The Christian is “to keep himself unspotted from the world” (James 1:27).
While it is true that these three definitions of “the world,” as (1) the material earth or universe, (2) the people on the earth, and (3) the things of the earth, each contribute something to the whole picture, it will already be apparent that behind them all is something more. The classical idea of orderly arrangement or organization helps us to grasp what this is. Behind all that is tangible we meet something intangible, we meet a planned system; and in this system there is a harmonious functioning, a perfect order.
It’s this third usage of “the world” that many (if not most?) Christians today do not grasp.
Is it possible that this is the reason for the increased worldliness among believers today?
Once we name something properly, we take away much of its power.