As per Lk 12:10. I know there have been cases when people freaked out thinking that they have sinned against the Holy Spirit and are therefore damned.
To avoid such mishaps, this point should be rightly understood. The very purpose of our existence in this world is to achieve unity or unities of different kinds:
between oneself and other people through (minimally) justice and (normally) charity;
between oneself and God through a combination of charity and religion;
between self and the material world through artistic mastery of nature and technological and economic improvement;
with one’s own body through health and fitness;
in the “big picture,” both complete, coherent, and true, contemplated by the mind through knowledge, understanding, and wisdom;
between one’s intellect and will through morally approving of all that one enjoys and through enjoying the things one morally approves of;
of the intellect itself through avoiding or curing mental illness, as psychosis, for example, is as if the mind is falling apart;
between one’s metaphysical goods (nature), moral goods or character (virtues), and physical goods (narrow happiness);
between the sensitive and intellectual appetites;
- between self and existence through (minimally) avoiding suicide and (normally) love and enjoyment of life.
All these unities require appropriate forms of love which is the 2nd-level unitive force. Love is of course a natural power but can be upgraded by God the Holy Spirit through grace.
Now reflect on the sacrifices God the Father has made in order to produce a world in which growth in love is possible.
He sacrificed billions of His angels, including the best created being ever, who became demons.
He sacrificed a massive amount of natural happiness for humans, for suffering in this world is ubiquitous, varied, and enormous.
He sacrificed His Son by bidding Him to receive the grace of charity for humans and then choose whether to accept the grace and love us or reject the grace and essentially destroy the world.
Sinning against the Holy Spirit, i.e., refusing to love or even hating what one ought to love instead, is acting contrary to the very purpose of life. Ignorance (sin against the Father) or weakness (against the Son) can be forgiven, as being obstacles to charity but not the essence of its contrary. Hatred (say, of other men or one’s own life), on the other hand, is an explicit act of defiance of God’s project and everything that living in this world is about.
The world in which each creature was first created in autonomous natural happiness is now to be unified as per the will of God into what eventually will be a far more astonishing and beautiful creation. Refuse to go along, and you may as well dive into hell right now.