Truly I say to you, all sins will be forgiven the sons of men, and whatever blasphemies they utter; but whoever blasphemes against the Holy Spirit never has forgiveness but is guilty of eternal sin. (Mark 3:28–29)
Only one thing puts a person beyond forgiveness: blaspheming against the Holy Spirit. But this is not any single act, for Jesus says any sins and blasphemies will be forgiven those who follow him. No. Blasphemy against the Spirit of God is treating the Spirit as dirt by continually and persistently resisting and rejecting this call to repentance until death.
No single sin, not even suicide, evicts a person from heaven into hell. One thing does: continual rejection of God’s Spirit. Our friend, we believe, gave up that resistance and accepted the forgiveness of Christ. What sort of momentary weakness, what brief cloud of hopelessness caused her to take her life remains a mystery. But no one can say this: that her final act is unforgivable. Nor any other act by any of us. For Jesus said: all sins will be forgiven the sons of men if they give up resisting the Spirit and look to Jesus for salvation.