Introduction Ours is an age of doubt, skepticism, and unbelief. Having rejected his Judeo-Christian heritage, modern man seeks meaning and purpose in Eastern religions, neo-paganism, environmentalism, and mesmerizing political messiahs. Thoughtful observers are herein reminded of the maxim, often attributed to Chesterton: “When a man stops believing in God he doesn¹t then believe in nothing, he believes anything.”

The Adjective The Greek adjective apistos, occurring 23x in the NT, a compound of the negative prefix and pistos [faithful, reliable], refers to that which is “unbelievable, incredible” (cf. Acts 26:8), or “without faith, disbelieving, unbelieving” (cf. Titus 1:15).

The Verb The verb apisteō, occurring 8x, means to “disbelieve, refuse to believe” (cf. Mark 16:16), or “be unfaithful of one lacking a sense of obligation” (cf. 2 Tim. 2:13).

The Noun The noun apistia, occurring 11x, signifies an “unwillingness to commit oneself to another or respond positively to the other’s words or actions, lack of belief, unbelief” (cf. Rom. 4:20), or a “lack of commitment to a relationship or pledge, unfaithfulness” (cf. Rom. 3:3).

Usage in the Gospels Eleven of the thirteen occurrences center around three events: the unbelief of the inhabitants of Nazareth in rejecting the ministry of Jesus; the unbelief of the disciples in their failure to cast out the demonic, and the unbelief of the disciples in rejecting the testimony of those who had seen the risen Savior.

Self-Defeating The inhabitants of Nazareth reveal that unbelief is self-defeating (Matt. 13:53-58; Mark 6:1-6).

Ineffective The failure of the disciples and the father of the demonic reveal that unbelief is ineffective (Matt. 17:14- 21; Mark 9:14-29; Luke 9:37-43).

Callous In rejecting the testimony of those who had seen the risen Savior, the disciples reveal that unbelief is callous and hard-hearted (Mark 16:9-14; Luke 24:1-11, 36-49; John 20:19-29).

Blindness Unbelief results in blindness (Acts 28:23-31; 2 Cor. 4:1- 6; John 12:37-40).

Defilement Unbelief results in defilement (Titus 1:15-16; cf. also Heb. 12:15-16; Jude 5-8).

Instability Unbelief results in instability (Rom. 4:19-22; 1 Pet. 2:4- 8; cf. also 2 Pet. 1:5-11).

Exclusion Unbelief results in exclusion, from Divine promises (Rom. 11:17-24; Heb. 3:12-19), and also from Christian fellowship (1 Cor. 6:1-6; 7:12-16; 10:23-30; 14:20-25; 2 Cor. 6:14-18).

Destruction Unbelief results in destruction (Mark 16:15-16; Luke 12:42-46; Rev. 21:5-8).

Conclusion In his unbelief and disobedience, man is lost and undone (1 Tim. 1:12-16; 5:3-8); however, Jesus Christ extends the promise of salvation to all those who believe and obey (Mark 16:15-16; John 3:36). Avoiding the instability of doubt and unbelief, let us grow up in all aspects into Him who is the head, even Christ (Eph. 4:11-16; James 1:5-8).