28 Anyone who has rejected Moses’ law dies without mercy on the testimony of two or three witnesses. 29 Of how much worse punishment, do you suppose, will he be thought worthy who has trampled the Son of God underfoot, counted the blood of the covenant by which he was sanctified a common thing, and insulted the Spirit of grace? (Hebrews 10:28–29, NKJV)
Moses’ law was clear concerning apostasy. The death penalty was applied under the Sinai law on the basis of two or three witnesses (Deuteronomy 13:6-10; 19:15). The author presents his case from the lesser to the greater. Transgressing Moses’ law brought sure punishment upon those who rejected it. The Christian (though previously “sanctified,” v. 29) is much worthier of death for rejecting the redemption he received through the blood of the covenant. God’s mercy has been provided through Christ’s sacrifice (Hebrews 10:26) – there is no other source of mercy. The Christian who sins willfully tramples on the Son of God. The blood of Christ, that dedicated the new covenant, is profaned by it. The Spirit of God, who revealed God’s grace to the world, is insulted by it. All this is written to Christians as a deterrent against willfully sinning against God. If you have done so, you can change you’re the will of your heart by repenting and renewing your life of faith (1 John 1:9; Acts 8:20-24). God’s mercy is still available to you in Christ. Rejecting God’s mercy will bring you eternal death. Choosing to live in sin is not worthy that!