APOSTASY
It means “to go back, to relapse” (Gr.).
Paul was accused of teaching the Jews among the Gentiles to apostatize from Moses (Acts 21:21). Paul taught freedom from the law through the death of Christ, and this, for a strict rabbinic Jew, would constitute apostasy, forgetting the promise of the New Covenant given by the prophet Jeremiah (Jer. 31:31-34, etc.).
This same word is used in Thessalonians (2 Thessalonians 2:3), where it is taught that the day of the Lord cannot come until “the apostasy” or abandonment of Christianity comes in connection with the manifestation of the man of sin. (See ANTICHRIST).
Regarding individual apostasy, it is discussed in passages such as Hebrews (Heb. 3:12; 10:26, 28), and in the Epistle of Jude. There are also warnings that this type of apostasy will become more widespread as the present dispensation closes (1 Tim. 4:1-3).
An apostasy necessarily implies a position from which one can fall, a profession made that is deliberately abandoned.
It is not a question of a Christian falling into some sin, but of a definite abandonment of Christianity by an unconverted professor, who has not experienced the regeneration of conversion. The Scriptures offer no hope for such a state.