The unforgivable sin—blasphemy against the Holy Spirit—is the subject of debate, curiosity, and even fear for many. Many scholars and theologians have tackled the subject, yet there is no definite interpretation shared by a majority. This thesis focuses on Mark 3:20-35 in an attempt to gain the best possible understanding of the ambiguous sin in question. While several methodologies are used to varying degrees, this thesis focuses on the biblical passage from a narrative-critical perspective. With all aspects of the story being taken into consideration, a few important conclusions are drawn. First and foremost, the unforgivable sin can be defined as intentionally sabotaging the work of God by calling it Satanic. Secondly, while Jesus mentions such a sin because of the scribes from Jerusalem, one cannot conclude that they are guilty of the sin; Jesus’ words may have been a warning. Thirdly, Jesus’ family is clearly depicted as an opponent of Jesus. Finally, if indeed the scribes are in danger of committing an unpardonable sin, so are Jesus’ mother, brothers, and sisters, since their actions are similar to those of the scribes. The importance of such conclusions is significant is both academic and religious circles.