Apostasy is the act of leaving a religion, either to convert to another religion, or to atheism, deism, or agnosticism.
In some theocratic countries apostasy is punishable by death. In most religions, apostasy is punishable by eternal damnation, a fate worse than death.
Sources defining and discussing the standard meaning of apostasy
Apostasy differs entirely from Heresy.
Heresy is the obstinate post-baptismal denial of one or more or almost all of the truths of the faith.
Apostasy is the obstinate, post-baptismal, total repudiation of Christianity, and the absolute rejection of the name and identity of "Christian". An apostate wants nothing to do with Christianity.
Compare The Great Heresies list of heresies committed by Catholics
Compare Lists of former Christians (wikipedia.org)
The word "Apostasy" and "Apostate" does not properly apply to anyone or to any church that (still) claims the name of Christian, however false their claim to be Christian might be. For example, those whom Paul called "false brethren, false apostles" (Galatians 2:4; 2 Corinthians 11:12-15). They may have departed from the truth, they may be guilty of formal and material heresy, they may have rejected every Christian doctrine, belief and practice in their teaching and preaching, they may be liars, they may be virtual atheists, but if they have been baptized and have not renounced the name of Christian they have not actually committed apostasy—even if some Christian commentators have ignorantly and improperly abused this word by saying such people are "apostates".
Many writers have redefined the following terms as equal to and synonymous with apostasy. They are not.
See examples of this improper usage of "apostasy" in the following articles:
By definition the term "Christian apostate" is an oxymoron. A man or woman may be a very bad Christian. That does not automatically make them apostate. Leaving one Christian denomination to join another is not apostasy.
The biblical text of Hebrews 6:4-6 is a direct reference to apostasy, a "falling away" or abandoning of Christ. The word παραπεσόντας parapesontas in verse 6 is translated as both "fall away" and "apostatize". It derives from the basic Greek word παραπίτω "parapiptõ" (KJV "fall" Strong's number 3895): "to fall aside, that is (figuratively) to apostatize."
“ | 4 For it is impossible for those who were once enlightened, 5 And have tasted of the heavenly gift, and were made partakers of the Holy Ghost, and have tasted the good word of God, and the powers of the world to come, 6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame. KJV (boldface emphasis added) | ” |
“ | 26 For if we sin willfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, 27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. 28 He that despised Moses' law died without mercy under two or three witnesses: 29 Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace? 30 For we know him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people. 31 It is a fearful thing to fall into the hands of the living God. KJV (see Transubstantiation) | ” |
Hebrews 6:6 is in the middle of a passage bookmarked by Melchizedek in Hebrews 5:10 through Hebrews 7:1 with everything in between as one progressive thought. The author of Hebrews began to explain the individual priesthood to the Hebrew Christians represented by Melchizedek but realized in Hebrews 5:11 that they had regressed in their faith and pointed out that they were now studying how to become born again to the point that they were even attempting to become born again a second time. As individual priests before God, Christians are supposed to confess their sins to God and not to seek to become born again a second time as the Hebrew Christians were doing.
Hebrews 6:6 Fallen away: Greek word is parapipto which is a compound of para (near or immediately next to; where English word parallel comes from) and pipto (to stumble or fall down) which could be translated as fallen beside. Parapipto (a verb) is used once in the Bible but the noun paraptoma (3900) is used often. Some examples: Galatians 6:1; 2 Corinthians 5:19; Ephesians 1:7 & 2:1; Romans 11:11 (stumbled first then fell). In the NASB it is translated as trespass(es) and transgression(s)
John 13:9-11 Peter wanted a second bath. Since Peter is immature at this point, Jesus provides a gentle explanation that once you are bathed (believe in Jesus Christ) you only need your feet washed. Priests in old testament bathed at home and then washed their feet at the temple. Foot washing represents God cleansing us from our sins while we are in the world. 2 Peter 1:9 Tells us that you can forget that you've been purged from old sins or forget you've been born again.
When Moses was at the waste place of Horeb, God commanded Moses to strike the rock with his rod of judgment (Exodus 17:5-6). Later at the sacred place of Kadesh, Moses was commanded to speak to the rock with Aaron's rod which had budded but instead took Aaron's rod and struck the rock a second time (Numbers 20:9 & 17:10). In the former, striking the rock represented Jesus on the cross bearing our judgment to provide salvation. In the later, speaking to the rock with Aaron's rod represents our priestly duties of confessing our sins post salvation (1 John 1:9). Striking the rock the second time caused God to not be hallowed (Numbers 20:12) and was sufficient to bar Moses from entering the promised land. To amplify, Hebrews 3:7-11, 15, 4:3 & 4:7 quote from Psalms 95:7-11 which speaks about the Meribah incident.
In John 11:21, 32 Martha and Mary said exactly the same things to Jesus but received entirely different responses. Martha was the busy body who did not want to study God's word and did not know much about God and even wanted to leave when Jesus was explaining things to her. Mary was the spiritually mature sister who used to sit at the feet of Jesus and therefore Jesus had higher expectations of her and therefore wept when Jesus saw the hopelessness of the people and the lack of spiritual witness by Mary.
The Corinthian church had always been immature and therefore there were lower expectations so we do not see words such as this in the letters to the Corinthians. The Hebrews had higher expectations since they had been mature and are therefore rebuked sharply for their attempts to become born again a second time.
Hebrews 10:26 can be understood by the word "We" or we Hebrews who have been relying on the laws and sacrifices for generations. If we Hebrews continue to rely on the laws and sacrifices after we have heard of Jesus Christ, then there is no more sacrifice.
See
multiple translations of Hebrews 6:6
multiple commentaries on Hebrews 6:6
the basic text of Hebrews 6:6 —παραπεσόντας "having fallen away" (from God)
100 Bible verses about Apostasy