In the epistle of Jude, the author describes certain false teachers as “merely natural, not having the Spirit” (v. 19). He seems to be stating plainly that these professing Christians are unbelievers. How can he make such a judgment?
Doesn’t Jesus say, “Do not judge, so that you won’t be judged” (Matt. 7:1)? Isn’t God the only one who may rightly search the hearts of people (Jer. 17:10)?
How can Jude possibly know that these interlopers are lost? Isn’t it possible they are merely deceived, or backslidden?
First, we should note that Jude describes these particular false teachers as “natural.” Literally, this means “animal-souled” and stands in contrast with “spiritual,” or “having the Spirit.” The apostle Paul describes the unbeliever as a “natural man” who “does not welcome what comes from God’s Spirit, because it is foolishness to him; he is not able to know it since it is evaluated spiritually” (1 Cor. 2:14).
Clearly, Jude and Paul are depicting people outside the kingdom of God. Jude’s use of the term psuchikos – soulish, sensual, animal-souled – describes them in sensual rather than spiritual terms.
As John MacArthur puts it, “His [Jude’s] materialistic description exposed them for who they really were – religious terrorists who lacked such internal qualities as a proper self-perception, the ability to reason, and a true knowledge of God. Even though the false teachers claimed a transcendental understanding of God, they did not know Him at all.”