The Bible contains serious warnings. Even the New Testament does:
Causes of Apostasy (Falling Away).
"For it is impossible, in the case of those who have once been enlightened,
who have tasted the heavenly gift, and have shared in the Holy Spirit,
and have tasted the goodness of the Word of God and the powers
of the age to come, and then have fallen away, to restore them again
to repentance, since they are crucifying once again the Son of God
to their own harm and holding him up to contempt." (Heb 6:4–6).
Apostasy (falling away) isn't the same as temporarily falling. Apostasy is the result
of a fall that isn't corrected. Peter fell, see The Apostle Peter, but didn't become
an apostate. He experienced correction. A fall can happen through surprise
or weakness. It's something unwanted, something that makes one sad
and from which one tries to rise (Mat 26:75). Apostasy, on the other hand,
consists of more or less consciously distancing oneself from God in a way
that can end in a complete rejection of the Lord and his revealed Word.
Judas is a tragic example, see Why Judas betrayed Jesus.
There are several types of apostasy that can take different forms.
Religiously, it can mean abandoning the service and worship of God
and turning to idolatry in one form or another. Intellectually, it can mean
despising and rejecting the Word of God. Morally, it can mean turning away
from God’s standards for an ethical life, individually and socially.
Believers can be led to apostasy through the activities of false prophets,
something that is often mentioned in the New Testament,
see Beware of false prophets in The Sermon on the Mount.
Believers can also be led to apostasy for other reasons, such as a lack of insight
into God's Word or sluggishness towards the Word (Heb 5:11), trials and worries (Luke 8:13), superficial pleasures and carnal desires (Luke 8:14),
love of money, see The Love of Money, and unfaithfulness (Heb 3:12).
Most often, apostasy begins with a fall that isn't corrected, and as a rule,
an inner fall occurs first, which then manifests itself in an outer fall.
Believers are preserved from apostasy by being on guard (2 Pet 3:17),
by growing in grace and knowledge of our Lord and Savior Jesus Christ (2 Pet 3:18), by testing the spirits (1 John 4:1), by openness to the Word and responsiveness
to the voice of the Holy Spirit, see Psalm 131: I have quieted my soul,
by nurturing the life of faith, see How to Build Your Faith, by walking in the Spirit (Gal 5:16), by fellowship with other believers and mutual encouragement
(Heb 10:24–25), and when one has fallen into sin by immediately making peace
with God (1 John 1:9), and also with people, see Forgive and You will Be Forgiven.
The New Testament's serious warnings against apostasy are based on the fact
that God has given people his decisive revelation in Christ (Heb 1:1–3).
Rejecting Christ therefore means apostasy from God (Heb 3:1, 12).
The fact that there are sins that are inherently unforgivable is because they can
lead the sinner to a situation where he doesn't want fellowship with God restored. There is no longer any receptivity to God's grace. Scripture expressly states
that the blood of Jesus, the Son of God, cleanses us from all sin (1 John 1:7),
and as surely as Christ's atoning work applies to all sin, so surely is this the only possibility of salvation for sinners, see Jesus, the Way, the Truth and the Life.
For more information, see The Book of Hebrews.
What about sinning deliberately after being saved?
"For if we go on sinning deliberately after receiving the knowledge of the truth,
there no longer remains a sacrifice for sins, but a fearful expectation of judgment, and a fury of fire that will consume the adversaries. Anyone who has set aside
the Law of Moses dies without mercy on the evidence of two or three witnesses.
How much worse punishment, do you think, will be deserved by the one who has trampled underfoot the Son of God, and has profaned the blood of the covenant
by which he was sanctified, and has outraged the Spirit of Grace?" (Heb 10:26–29).
There are two elements in these verses:
- To consciously reject the truth, which here is the same as God's total message of revelation and not just individual commandments in the law.
- Holding on to the state of sin without wanting to be called to repentance.
Already in the Old Testament a distinction is made between sin "by mistake"
and sin "with deliberate courage", that is, in defiance, consciously and deliberately (Num (4 Mos) 15:22–31). Scripture distinguishes between sin that is committed because the will is weak and is overcome by the tempter,
and deliberate sin that one wants and chooses to commit.
The Book of Hebrews is a coherent exhortation to Jewish Christians who,
because of suffering and opposition from surrounding Judaism, were on the verge
of giving up their faith in Christ. It's in this light that we must also read this exhortation. Unforgivable sin is linked to "despising the blood of the covenant" (see Jesus and the Law), and "grieving the Spirit of Grace" (Heb 10:29).
What about blasphemy against the Holy Spirit?
"Therefore I tell you, every sin and blasphemy will be forgiven people,
but the blasphemy against the Spirit will not be forgiven. And whoever speaks
a word against the Son of Man will be forgiven, but whoever speaks against
the Holy Spirit will not be forgiven, either in this age or in the age to come."
(Mat 12:31–32).
See these verses explained in detail in The Unforgivable Sin.
See also Some stories in the gospels at the end of The Four Gospels.
