Hebrews 10:23-27
23 Let us hold fast the profession of our faith without wavering; (for he is faithful that promised;)
24 And let us consider one another to provoke unto love and to good works:
25 Not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.
26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
You are wasting your breath/energy/time.
Hebrews 10:28–30 (TC):
“Taken cumulatively, the three clauses in v 29 define persistent sin (v 26a) as an attitude of contempt for the salvation secured through the priestly sacrifice of Christ. Nothing less than a complete rejection of the Christian faith satisfies the descriptive clauses in which the effects of the offense are sketched.”
“Willful rebels under the Old Covenant only lost their lives (cf. Deut. 17:2–7; 13:8), but willful rebels under the New Covenant lose an eternal reward. Not only so but God often begins to punish modern apostates in this life.
“It was commonly inferred [incorrectly] in the Early Church from this and other passages in the epistle that forgiveness for all kinds of post-baptismal sin, inadvertent as well as deliberate, was ruled out.”
10:30–31
“In Deuteronomy 32, which the writer quoted here twice (Deut. 32:35–36, 40–41), Moses warned the Israelites against apostatizing. That was this writer’s point here as well. It is a terrifying prospect for a believer who has renounced his or her faith to fall under God’s hand of chastisement. Note that the writer addressed this warning to believers, though many interpreters have applied it to unbelievers.
“Actually, Heb. 10:30, 31 forms a parallel reference to II Cor. 5:10, 11, and the preceding verses (vv. 26–29) provide additional information concerning that facet of the judgment seat associated with the ‘terror of the Lord.’”