the sin against the Holy Ghost can be forgiven.

Obj. 3: Further, the free-will is indifferent to either good or evil.
Now, so long as man is a wayfarer, he can fall away from any virtue,
since even an angel fell from heaven, wherefore it is written (Job
4:18, 19): "In His angels He found wickedness: how much more shall
they that dwell in houses of clay?" Therefore, in like manner, a man
can return from any sin to the state of justice. Therefore the sin
against the Holy Ghost can be forgiven.

_On the contrary,_ It is written (Matt. 12:32): "He that shall speak
against the Holy Ghost, it shall not be forgiven him, neither in this
world, nor in the world to come": and Augustine says (De Serm. Dom. in
Monte i, 22) that "so great is the downfall of this sin that it cannot
submit to the humiliation of asking for pardon."

_I answer that,_ According to the various interpretations of the sin
against the Holy Ghost, there are various ways in which it may be said
that it cannot be forgiven. For if by the sin against the Holy Ghost
we understand final impenitence, it is said to be unpardonable, since
in no way is it pardoned: because the mortal sin wherein a man
perseveres until death will not be forgiven in the life to come, since
it was not remitted by repentance in this life.

According to the other two interpretations, it is said to be
unpardonable, not as though it is nowise forgiven, but because,
considered in itself, it deserves not to be pardoned: and this in two
ways. First, as regards the punishment, since he that sins through
ignorance or weakness, deserves less punishment, whereas he that sins
through certain malice, can offer no excuse in alleviation of his
punishment. Likewise those who blasphemed against the Son of Man
before His Godhead was revealed, could have some excuse, on account
of the weakness of the flesh which they perceived in Him, and hence,
they deserved less punishment; whereas those who blasphemed against
His very Godhead, by ascribing to the devil the works of the Holy
Ghost, had no excuse in diminution of their punishment. Wherefore,
according to Chrysostom's commentary (Hom. xlii in Matth.), the Jews
are said not to be forgiven this sin, neither in this world nor in
the world to come, because they were punished for it, both in the
present life, through the Romans, and in the life to come, in the
pains of hell. Thus also Athanasius adduces the example of their
forefathers who, first of all, wr