As used here, apostasy refers to a
departure from or denial of the Christian faith by someone who once held to it.
There are several views about what happens to someone who leaves the faith.
Some say a true Christian will never apostasize. Some say a true Christian can
leave the faith, but he or she loses salvation. Others say a true Christian can
depart from the faith, perhaps never return, yet never lose his or her
salvation, but suffers other consequences.
It is easy to demonstrate that apostasy is taught or seen in the Bible. Consider these passages:
It is clear from the passages listed above that those who apostasize are true Christians, otherwise the descriptions, warnings, and exhortations are empty and meaningless. The very idea that someone strays from something implies they once adhered to it. A person cannot desert something or some place that he or she has never experienced.
Verse 11 obviously speaks of our union with Christ that is a consequence of our salvation (Rom. 6:3-5; Gal. 2:20). Those who are saved will live forever with Christ. This speaks sufficiently to the impossibility of losing salvation. Verse 12, however, speaks of a different condition and a different consequence. The condition is endurance, which is often exhorted of Christians (e.g., 2 Tim. 2:3; Heb. 10:23, 36; 12:1; James 1:2-4, 12) and refers to perseverance in trials and suffering. The consequence of reigning does not refer to salvation, but to the reward for faithfulness—reigning with Christ in His kingdom. This reward is clearly taught in many other passages (Luke 19:1119; Rev. 2:26-27; 3:21; Rev. 22:3-5). If we deny Christ by not enduring faithfully in trials, then He denies us His approval and reward (cf. Matt. 10:33; Luke 19:20-27). Verse 13 then speaks of another circumstance altogether. If we are “faithless” (apisteuo, without faith, unbelieving; cf. Rom. 3:3), God remains “faithful” (pistos). What is God faithful to? He is faithful to His promise that we will live with Him forever, as stated in verse 11 (cf. John 3:16; 5:24; 11:24-26). This does not refer to verse 12 because it is intended as a comfort. It would be incongruous to appeal to the positive attribute of God’s faithfulness to affirm God’s negative discipline.