The book of Hebrews is a book of exhortation written to believers (13:22), yet within it there are repeated warnings concerning apostasy . To read about the exhortations in Hebrews follow this link:
THE WARNINGS TO BELIEVERS IN HEBREWS
The first warning (Hebrews 2:1-3) tells us that neglecting our great salvation will result in punishment just as disobedience to the words spoken by angels (under the Law) also resulted in punishment.
The second warning (Hebrews 3:7- 4:1) exhorts us not to harden our hearts to the voice of the Holy Spirit through unbelief. In this section we are reminded that God swore in His wrath that those who provoked Him in the wilderness also died in the wilderness and did not enter into His rest.
We are warned that we need to fear God so that we do not become like those in the wilderness who fell short of entering His rest (which according to the context is eternal rest). It is clear from the context that the same God who swore in His wrath, they shall not enter my rest and did not spare those who rebelled in the wilderness will not spare us either if we become hard hearted through unbelief and the deceitfulness of sin.
The third warning (Hebrews 5:11-6:20) is against slothfulness which results in apostasy. We are told in very clear and precise terms that if we become slothful in our faith we are in danger of being condemned and cursed.
The fourth warning (Hebrews 10:26-39) is against willfully sinning and drawing back. Here is what Hebrews 10:26-31 says:
Dear friends, if we deliberately continue sinning after we have received knowledge of the truth, there is no longer any sacrifice that will cover these sins. There is only the terrible expectation of God’s judgment and the raging fire that will consume his enemies. For anyone who refused to obey the Law of Moses was put to death without mercy on the testimony of two or three witnesses. Just think how much worse the punishment will be for those who have trampled on the Son of God, and have treated the blood of the covenant, which made us holy, as if it were common and unholy, and have insulted and disdained the Holy Spirit who brings God’s mercy to us. For we know the one who said, “I will take revenge. I will pay them back.” He also said, “The LORD will judge his own people.” It is a terrible thing to fall into the hands of the living God.
The fifth warning (Hebrews 12:14-29) sums up all the other warnings – beware of sin and rejection of Jesus.
Many of you recognize the words “our God is a consuming fire” but do you know the context of these words? Many quote this in connection with God’s love, but the scriptures do not use it that way. These words, in both the Old and New Testament, are used in connection with God’s holiness and righteous judgment against sin (i.e. His jealously expressed in anger which results in the punishment of our sins).
Here is how Moses used the words:
But the LORD was angry with me because of you. He vowed that I would not cross the Jordan River into the good land the LORD your God is giving you as your special possession. You will cross the Jordan to occupy the land, but I will not. Instead, I will die here on the east side of the river. So be careful not to break the covenant the LORD your God has made with you. Do not make idols of any shape or form, for the LORD your God has forbidden this. The LORD your God is a DEVORING FIRE; he is a jealous God. “In the future, when you have children and grandchildren and have lived in the land a long time, do not corrupt yourselves by making idols of any kind. This is evil in the sight of the LORD your God and will arouse his anger. (Deuteronomy 4:21-25 TNLT)
The King James Version says: consuming fire (v.24) instead of devoring fire – “For the LORD thy God is a consuming fire, even a jealous God.” This is exactly how the Book of Hebrews uses this description of God. Now notice the context from Hebrews 12:25-28:
Be careful that you do not refuse to listen to the One who is speaking. For if the people of Israel did not escape when they refused to listen to Moses, the earthly messenger, we will certainly not escape if we reject the One who speaks to us from heaven! When God spoke from Mount Sinai his voice shook the earth, but now he makes another promise: “Once again I will shake not only the earth but the heavens also.” This means that all of creation will be shaken and removed, so that only unshakable things will remain. Since we are receiving a Kingdom that is unshakable, let us be thankful and please God by worshiping him with holy fear and awe. For our God is a devouring fire.
The KJV says: “…let us have grace, whereby we may serve God acceptably with reverence and godly fear: For our God is a consuming fire.”