In contrast to the true revelation of God ( 1 Timothy 3:16), false teaching would arise as time passed. Whether Paul referred to a special revelation he had received by the Holy Spirit or simply to previously revealed revelation ("the Spirit explicitly says") we cannot determine for sure. Nevertheless God had revealed through Christ that as time passed some who held the truth would repudiate it ( Matthew 13:21; Matthew 24:10-11; Mark 4:17; Mark 13:22; Luke 8:13; cf. Acts 20:29; 2 Thessalonians 2:1-12; 2 Timothy 3:1-13; 2 Peter 3:1-18). This would come about as a result of their listening to persuasive arguments put forth by God"s spiritual enemies and, behind them, demons ( 1 Timothy 4:1). [1][source]
". . . one of Paul"s concerns here is almost certainly to arrest any doubts about the permanence of God"s church." [2][source]
Are these who fall away from the truth believers or unbelievers? The Greek verb Paul used to describe their activity (aphistemi, to withdraw from, lit. to stand away) and the noun he used to describe their action (apostasia, defection, apostasy) do not answer this question. Either could be in view. The context must determine whether the one departing is a believer or an unbeliever. In some passages the context argues for Christian apostates (called "backsliders" by some Christians; Luke 8:13; 1 Timothy 1:18-20; 1 Timothy 4:1; 1 Timothy 6:20-21; Hebrews 3:12; cf. 2 Timothy 2:12 b, 16-18; 1 Timothy 3:13; 1 Timothy 4:3-4). A Christian who follows the impulses of his or her sinful human nature rather than those of the Holy Spirit is a carnal believer ( 1 Corinthians 3:3). [source][source][source]
"It comes as a shock to some people that Satan uses professed Christians in the church to accomplish his work. But Satan once used Peter to try to lead Jesus on a wrong path ( Matthew 16:21-23), and he used Ananias and Sapphira to try to deceive the church at Jerusalem ( Acts 5). Paul warned that false teachers would arise from within the church ( Acts 20:30)." [3][source]
In other passages the context points to non-Christian apostates ( Luke 13:27; cf. 2 Thessalonians 2:11). In still other passages either or both may be in view; we do not have sufficient information in the context to say ( 2 Thessalonians 2:3; cf. Titus 1:14). It seems quite clear that Christians can stop believing God ( Matthew 10:33; Mark 8:32; 2 Timothy 2:12; Revelation 3:8). [4] This does not mean, however, that they will lose their salvation since salvation is God"s work, not ours ( John 10:28; Romans 8:31-39; 2 Timothy 2:13). One of my professors at Dallas Seminary used to say, correctly, I think, "I believe in the perseverance of the Savior, but I do not believe in the perseverance of the saints." [5][source]
These apostates had developed cauterized consciences by refusing to respond to the truth that they knew. Now they called lies the truth, and that is hypocrisy ( 1 Timothy 4:2). [source][source][source]
The teaching of the apostates Paul warned Timothy and the Ephesians to watch out for was asceticism (cf. Colossians 2:20-23). Asceticism is the idea that abstinence from physical things is essential for spiritual purity. Specifically these teachers forbade marriage and the eating of some foods. Probably Gnostic teaching that later achieved its most influential strength in the second century A.D. had influenced them. Gnosticism taught that matter was evil and people should try to live with as little attachment to physical things as possible. Judaism appears to have been another root influence on these teachers since it taught that some foods were fit (Heb. kosher) and others unclean (cf. Colossians 2:16-17). There may be physical reasons for not eating certain foods (e.g, allergies, too high fat content, etc.), but there are no spiritual reasons. Likewise there may be physical reasons why in individual cases marrying may not be wise or desirable (e.g, passing on genetic defects, the demands of a particular ministry, etc.). Nevertheless God has approved the institution of marriage. [source][source][source]
Paul reminded his readers that God created marriage and food for us to enjoy ( 1 Timothy 4:3). Since the coming of Christ, the distinction between clean and unclean foods is one we can eliminate ( Mark 7:19; Acts 10:15; Romans 14:14; 1 Corinthians 10:23-33). [source][source][source]