No. I think one can say absolutely and definitely that the unpardonable sin is not suicide. Jesus speaks about the unpardonable sin in a very particular context. It seems to be an ongoing settled resistance to Jesus Christ that is simultaneously a rejection of the convicting ministry of the Holy Spirit.
Many people become concerned that they have committed the sin against the Holy Spirit. I had a friend who told me that when someone said to him, “I think I’ve committed the sin against the Holy Spirit,” the first thing he would say was, “Well, first of all, let’s talk about the forgivable sins.” They think they have committed the unforgivable sin, and the real test of whether they want forgiveness is to talk about the forgivable sins. That really tests whether people actually want forgiveness. If they’re not wanting forgiveness, then it’s not possible to bring comfort, peace, and assurance to them.
I think that helps us deal with the situation of people who say they have committed the unforgivable sin. But clearly in the Gospels when Jesus speaks about it, it’s a permanent and irrevocable rejection of Jesus Christ, even though the Holy Spirit has given every evidence to you that Jesus Christ is the Son of God. In that sense, it’s not related to suicide per se, although that was actually what it often got connected with in the medieval tradition.