Apostasy means a falling away. Therefore when we speak of apostasy in the Christian church we are speaking of the visible church falling away from the essential doctrinal truths and becoming false. Notice, I said “visible church”. The visible church is the earthly organization(s) that claim to follow Christ as found in the Bible. There are numerous denominations and not all of them believe the same thing when it comes to the essentials of the Christian faith. However, when they deny the essentials they are false and are no longer Christian.

To apostatize means to abandon previously held beliefs. This abandonment can be intentional or accidental. There can be individuals and or denominations that purposely repudiate the essential doctrines of the Christian faith. There can also be individuals and or denominations that do not intentionally abandon the basics of Christian doctrine but have gradually moved away from them.

The Bible says there are different reasons for apostasy.

• Desires
  • “For the time will come when they will not endure sound doctrine; but wanting to have their ears tickled, they will accumulate for themselves teachers in accordance to their own desires,” (2 Timothy 4:3).
• False teachers
  • “Many false prophets will arise and will mislead many,” (Matthew 24:11).
  • “For false Christs and false prophets will arise and will show great signs and wonders, so as to mislead, if possible, even the elect,” (Matt. 24:24).
  • “But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons,” (1 Timothy 4:1).
• Persecution
  • “Then they will deliver you to tribulation, and will kill you, and you will be hated by all nations because of My name. 10 At that time many will fall away and will betray one another and hate one another,” (Matthew 24:9-10).
  • “and they have no firm root in themselves, but are only temporary; then, when affliction or persecution arises because of the word, immediately they fall away,” (Mark 4:17).
• Temptation
  • “Those on the rocky soil are those who, when they hear, receive the word with joy; and these have no firm root; they believe for a while, and in time of temptation fall away,” (Luke 8:13).
• Unbelief
  •  “Take care, brethren, that there not be in any one of you an evil, unbelieving heart that falls away from the living God,” (Hebrews 3:12).

Not only can there be doctrinal apostasy but there can also be moral apostasy where those who claim to follow Christ become morally corrupt and seek sin rather than Christ.

The Bible talks about apostasy in different ways. Some of the terms used to describe it are…

• Forsaking the Lord
  • “Have you not done this to yourself by your forsaking the LORD your God when He led you in the way?” (Jeremiah 2:17).
• Falling away
  • “At that time many will fall away and will betray one another and hate one another,” (Matthew 24:10).
  • “But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons,” (1 Timothy 4:1).
• Rebellion
  • “For he adds rebellion to his sin. He claps his hands among us, and multiplies his words against God,” (Job 34:37).
  • “Against whom do you jest? Against whom do you open wide your mouth and stick out your tongue? Are you not children of rebellion, offspring of deceit, (Isaiah 57:4).

In the Old Testament, there is mention of apostasy, משׁובה, mashubah

• “Your own wickedness will correct you, and your apostasies will reprove you. Know therefore and see that it is evil and bitter for you to forsake the LORD your God,” (Jeremiah 2:19).
• “Therefore a lion from the forest will slay them. A wolf of the deserts will destroy them. A leopard is watching their cities. Everyone who goes out of them will be torn in pieces because their transgressions are many. Their apostasies are numerous,” (Jeremiah 5:6).
• “I will heal their apostasy, I will love them freely, for My anger has turned away from them,” (Hosea 14:4).

In the New Testament, there is mention of apostasy, ἀποστασία, apostasía

• “Let no one in any way deceive you, for it will not come unless the apostasy comes first, and the man of lawlessness is revealed, the son of destruction,” (2 Thessalonians 2:3).