Blasphemy against the Spirit.The Pharisees repeatedly rejected Jesus’ claims to be the Messiah/Savior. Their unbelief brought about the increasing hardening of the heart (Rom. 1:18-32; Eph. 4:17-19) that led to accusing Jesus of being an agent of the devil. It is possible for anyone to harden his heart to the point where God seals him in that hardness (Rom. 9:18). Once this point is reached, there is no chance of repentance or faith. The unforgivable sin is continued refusal to believe in Jesus Christ (Matt. 21:41; John 3:16-19, 36).