Apostasy is probably the biggest problems and greatest sin there is in the Bible, save the sin against the Holy Spirit. The scriptures are pretty blunt about it.

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. (Heb 6:4-6)

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. (Heb 10:26-27)

Paul wrote these words, probably fairly early in his Apostolic career, though thedetails about the authorship of this book is still widely debated. I think he wrote it early because unlike his other letters its emphasis was on the Jewish believers, rather than Gentiles Christians which were the focus of his life and ministry until he was martyred, even at one point calling himself 'Apostle to the Gentiles' (Rom 11:13).

These Jewish Christians were feeling a lot of persecution for other Jews for having believed in Christ. Paul had to lay it pretty hard on the line to let them know that the cost of Apostasy is far greater than they thought.

The temptation to 'go back' was strong. For the Jewish Christians of the 1st century, they faced persecution from the Romans, the cold shoulder from their own people as well as the difficulties of Christian life. The temptation must have been strong for many of them.

Paul dealt with their fears forcefully and scripturally showing them that Christ was indeed the fulfillment of the Jewish law. Paul was also of Jewish descent and knew exactly what they were facing and feeling.

They were experiencing the subtle calls of social and cultural reintegration with the Jewish communities in which they lived. Jews who then believed on the Messiah were often cast out of the temples and were not socially welcome among many Jews, not unlike today.

This was very difficult for them. Paul's intention in this letter is clear, to let the believers know that Christ was the fulfillment of the old Jewish law and that their faith in him is not in vain, if they keep the faith and not draw back from the Messiah.

This appears to be the theme throughout the letter, a powerful explanation of the Jewish law and its pointing the Jesus Christ as its fulfillment with a strong undercurrent of constant warnings throughout about the dangers of falling away from the faith.

Yet I feel led to say this about the verse above (Heb 10:26); Paul appears to be referring not to a single act of sin ('if we sin willfully') but of a state of sin, rebellion and obstinacy about that sin. Paul is referring to a heart that is apostatizing or in the process of doing so (which is what the letter is mostly about).

He is warning us of the deceitfulness of sin and the hardness of heart and soul that can result.

Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God. But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.(Heb 3:12-13)

The problem of Apostasy of course, does not just trouble believers of who are Jews, but also those of us who are gentiles. The problem is a real one, especially in these troubled times as Christ warned that there would be a literal epidemic of Christians falling away as the day of his return approaches.

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