The word “blasphemy” in its various forms (as verb, noun, adjective, etc.) appears some fifty-nine times in the New Testament. It has a variety of renderings, such as, “blasphemy,” “reviled,” “railed,” “evil spoken of,” “to speak evil of,” etc. Examples of these various renderings are: “They that passed by reviled him” (Matthew 27:39). “He that shall blaspheme” (Mark 3:29). “They that passed by railed on him” (Mark 15:29). “The way of truth shall be evil spoken of ” (2 Peter 2:2). “These speak evil of those things” (Jude 10). It is evident from these that blasphemy is a sin of the mouth, a “tongue-sin.” All New Testament writers except the author of Hebrews use the word (1936, pp. 224-225).
Furthermore, Jesus defined the term when, after referring to blasphemy, He used the phrase “speaks a word against” in Matthew 12:32.
WHAT THE UNPARDONABLE SIN IS NOT
With the working definition of blasphemy meaning, “to speak against,” or “speak evil of,” it is easy to rule out several sins that would not qualify as the unpardonable sin. Occasionally, murder is suggested as the “unpardonable sin.” Such cannot be the case, however. First, since blasphemy is a “tongue sin,” murder would not fall into this category. Second, several biblical passages show the sin of murder can be forgiven. When King David committed adultery and had Uriah the Hittite murdered, the prophet Nathan came to him, informing him that God had seen that David “killed Uriah the Hittite with the sword” (2 Samuel 12:9). When David confessed to Nathan and repented, the prophet told David, “The Lord also has put away your sin; you shall not die” (12:13). And, although David was punished for his iniquity, it was forgiven. The Bible plainly demonstrates that murder is not the unpardonable sin.