Hebrews 10:26

For if we sin wilfully - If we deliberately, for fear of persecution or from any other motive, renounce the profession of the Gospel and the Author of that Gospel, after having received the knowledge of the truth so as to be convinced that Jesus is the promised Messiah, and that he had sprinkled our hearts from an evil conscience; for such there remaineth no sacrifice for sins; for as the Jewish sacrifices are abolished, as appears by the declaration of God himself in the fortieth Psalm, and Jesus being now the only sacrifice which God will accept, those who reject him have none other; therefore their case must be utterly without remedy. This is the meaning of the apostle, and the case is that of a deliberate apostate - one who has utterly rejected Jesus Christ and his atonement, and renounced the whole Gospel system. It has nothing to do with backsliders in our common use of that term. A man may be overtaken in a fault, or he may deliberately go into sin, and yet neither renounce the Gospel, nor deny the Lord that bought him. His case is dreary and dangerous, but it is not hopeless; no case is hopeless but that of the deliberate apostate, who rejects the whole Gospel system, after having been saved by grace, or convinced of the truth of the Gospel. To him there remaineth no more sacrifice for sin; for there was but the One, Jesus, and this he has utterly rejected.