Q. If someone like an atheist, who previously rejected Christ, but later in life accepts him as their savior, then he is forgiven. Is not the Blasphemy of the Holy Spirit then essentially when a person is in a position where they permanently reject Christ?
A. I’m not sure it’s possible for any one other than the Pharisees of Matt. 12 to commit the sin of blasphemy of the Holy Spirit. When unbelievers do this, they don’t really know what they’re doing and it’s the intent of our heart that matters to God. Since the Holy Spirit is sealed within believers, it’s impossible for us to commit this sin. But the Pharisees knew what they were doing and “with malice aforethought” attributed the Lord’s miraculous power to Satan.
For us, the only unforgivable sin is to permanently reject the pardon that the Lord purchased for each one of us with His own blood. When we do that, we’ve said no to the only remedy that God has provided for us, and therefore our sins can’t be forgiven.