Both the Old and New Testaments teach clearly that God welcomes all sinners who repent, granting them forgiveness and salvation.  Both Testaments also teach that one who has been forgiven and wilfully and deliberately forsakes God and returns to a life of sin is lost.

There is much confusion in our time about this.  Much is said about the love of God and His compassion, which is all true, but what is not mentioned is that the person who forsakes God separates himself from the love and compassion of God.

We are sinful by nature and all unrighteousness is sin, but sins that are not willful and deliberate are covered by the canopy of grace.  We will not be lost every time we react with impatience or anger in the stresses of life.  We will not be lost every time that we neglect to do something that we should have done.  These things are sin, because they are unrighteous.  Yet God “knoweth our frame; he remembereth that we are dust” (Psalm 103:14) and is merciful.

In the Old Testament there was provision for one who sinned in ignorance to offer a sacrifice for such a sin once he became aware of it and be forgiven.  Such sins do not separate us from God, or cause spiritual death.  The apostle John instructs us to pray for a brother or sister who does something that is not a death sin.  We have the privilege to act as a priest on behalf of our brother or sister and pray that the shed blood of our Saviour will atone for such a sin.

But we cannot pray that God would forgive a deliberate sin, a sin unto death.  This does not mean that those who commit such a sin have no possibility of forgiveness, or that we should not pray for them at all.  We certainly can, and must, pray that God would call them once again to repentance.  We also have a responsibility to speak to our brother and sister about their need to repent and to point them once more to the cross of Calvary.

As born again Christians, we are covered by the blood and sheltered under God’s canopy of grace.  Under that canopy we are free and can rejoice in the love and peace of God.  But we dare not pretend that this canopy will extend far enough to cover deliberate, willful sin.

Neither salvation nor damnation are hereditary
Ezekiel 18:4 Behold, all souls are mine; as the soul of the father, so also the soul of the son is mine: the soul that sinneth, it shall die.

Ezekiel 18:20-21 The soul that sinneth, it shall die. The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son: the righteousness of the righteous shall be upon him, and the wickedness of the wicked shall be upon him.  But if the wicked will turn from all his sins that he hath committed, and keep all my statutes, and do that which is lawful and right, he shall surely live, he shall not die.

God desires the salvation of the wicked, yet willful sin separates us from God
Ezekiel 18:23-24  Have I any pleasure at all that the wicked should die? saith the Lord GOD: and not that he should return from his ways, and live? But when the righteous turneth away from his righteousness, and committeth iniquity, and doeth according to all the abominations that the wicked man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he die.

Ezekiel 18:30-32  Therefore I will judge you, O house of Israel, every one according to his ways, saith the Lord GOD. Repent, and turn yourselves from all your transgressions; so iniquity shall not be your ruin. Cast away from you all your transgressions, whereby ye have transgressed; and make you a new heart and a new spirit: for why will ye die, O house of Israel? For I have no pleasure in the death of him that dieth, saith the Lord GOD: wherefore turn yourselves, and live ye.

If we sin wilfully after we are converted, the sacrificial blood of Jesus Christ no longer covers our sin.
Hebrews 10:26-27  For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, but a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.

Hebrews 6:4-6  For it is impossible for those who were once enlightened, 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, 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.

2 Peter 2:20-21  For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning. For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them. But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.

Sins done through human weakness do not separate us from God
Numbers 15:28 And the priest shall make an atonement for the soul that sinneth ignorantly, when he sinneth by ignorance before the LORD, to make an atonement for him; and it shall be forgiven him.
1 John 5:16-17  If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it.  All unrighteousness is sin: and there is a sin not unto death.