Some challenge the Calvinist doctrine based on their interpretation of the admonishments in the book of Hebrews, including several passages in the Book of Hebrews, but especially and . The former passage says of those "who have once been enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit, and have tasted the goodness of the word of God and the powers of the age to come" that, when they "fall away", they cannot be "restored to repentance." The latter passage says that if one continues in sin, "no sacrifice for sins" remains for that person but "only a fearful expectation of judgment." The author of Hebrews predicts grave punishment for one who "has trampled the Son of God under foot, who has treated as an unholy thing the blood of the covenant that sanctified him, and who has insulted the Spirit of grace."