I read a blog post recently by a minister who no longer believes in God. The amazing thing of course is that he’s still a minister – which doesn’t make a lot of sense but the puzzlement didn’t end there. The reason he wrote was to protest those who keep telling him he is no longer a Christian. In other words, he claims to be an unbeliever and a Christian.
There are basic things one must believe and do in order to become a Christian. There are also basic things one must believe and practice in order to live out the calling of Christ. But let’s be perfectly clear: once one becomes a Christian, regardless of belief or practice, one never ceases to be a Christian, a child of God. One may lose his way, leave the way, lose his heavenly inheritance and bring shame on the family of God by poor behavior, but no matter what, that person remains a child of God.
When talking about essentials of the faith, the really important items are those whose absence cause us to fail at being children of God.
For example: The Corinthian Christians were Paul’s “problem children.” Some were haughty, some immoral, some disruptive. All these things compromised their Christian claim and threatened their eternal inheritance, but it did not change who they were. They were still Christians, God’s holy people. They just weren’t living like God’s holy people, and that was the problem. The sham that was their lives shamed God’s name.
The really big issue is whether a Christian can lose his inheritance in the kingdom of God. It is an inheritance promised by God and can never, on its own perish, spoil, or fade. Like an inheritance in any family however, it can be lost.
But there is something else.
There is not only eternal loss of inheritance awaiting the impenitent. There is the prospect of increased punishment. Why increased punishment? Because we are God’s children, and are responsible for knowing better.
 Paul refers to them as the “church of God,” those “sanctified.” The word “sanctified” means to “be made holy.” But Paul goes on to say that these who have been made holy are called to be holy (see 1 Corinthians 1:2). In other words, you’ve got to live up to what God has made of you.
 Hebrews 6:12; 9:15
 1 Peter 1:4
 1 Corinthians 6:9-10; Galatians 5:20-21; Ephesians 5:5. The reader should note that Paul, in all of these passages, is not writing about non-christians, but about Christians who engage in these behaviors.
 Hebrews 10:26-31 – 26 If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, 27 but only a fearful expectation of judgment and of raging fire that will consume the enemies of God. 28 Anyone who rejected the law of Moses died without mercy on the testimony of two or three witnesses. 29 How much more severely do you think a man deserves to be punished who has trampled the Son of God under foot, who has treated as an unholy thing the blood of the covenant that sanctified him, and who has insulted the Spirit of grace? 30 For we know him who said, “It is mine to avenge; I will repay,” and again, “The Lord will judge his people.” 31 It is a dreadful thing to fall into the hands of the living God.