We have probably all heard of or known someone who has fallen to apostasy. There are two ways this can happen. Apostasy is in simple terms ‘leaving the faith’. Some people like those in the church in Galatia have traded the truth for a lie, and have fallen to apostatism. (Gal 1:6-8) “I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel: {7} Which is not another; but there be some that trouble you, and would pervert the gospel of Christ. {8} But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.”
The second way that apostatism attacks the church comes in the form of simply leaving the church or the faith. A look at the context of Hebrews 10:25, which speaks of forsaking (meaning to desert, to give up or renounce) the assembling of our selves together, lets us know that the Hebrew writer is concerned about more than the occasional absence. He refers in verse 23 of holding to the profession of faith. (Heb 10:23-25) “Let us hold fast the profession of our faith without wavering; (for he is faithful that promised;) {24} And let us consider one another to provoke unto love and to good works: {25} Not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.” There are many who once held to the faith, but have for one reason or another renounced that faith either literally by words, or by allowing their actions to speak for them.
So regardless of whether an individual leaves the faith like Demas by desertion, or like Alexander and Hymanaeus have blasphemed by changing the truth of God for a lie that individual has succumbed to apostatism. (2 Tim 4:10) “For Demas hath forsaken me, having loved this present world, and is departed unto Thessalonica; Crescens to Galatia, Titus unto Dalmatia.” (1 Tim 1:19-20) “Holding faith, and a good conscience; which some having put away concerning faith have made shipwreck: {20} Of whom is Hymenaeus and Alexander; whom I have delivered unto Satan, that they may learn not to blaspheme.”
(2 Pet 2:1) But there were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction.