Blasphemy
Blasphemy in its primary biblical sense denotes speech or action that dishonors God—speaking against his name, his character, or his works in a way that denies his majesty, goodness, or power. The Old Testament prescribes the death penalty for blasphemy: the law of Leviticus 24:10-16 records the case of the son of an Israelite woman and an Egyptian father who blasphemed the Name and cursed God, and was stoned by the whole congregation. The same law applies equally to the native Israelite and the sojourner.
Blasphemy carries particular weight in the New Testament context, where Jesus declares that blasphemy against the Holy Spirit—the deliberate and persistent attribution of his work by the Spirit to Satan—is an unforgivable sin that will never be forgiven in this age or the age to come. The authorities accused Jesus himself of blasphemy for claiming the authority to forgive sins and for declaring himself the Son of God, making blasphemy the formal charge on which he was condemned before the Sanhedrin. The book of Revelation describes the beast as covered with blasphemous names and as opening its mouth in blasphemy against God. The New Testament broadens the concept to include any slander against God's name caused by the misconduct of those who bear it: the name of God is blasphemed among the Gentiles because of you.