We proceed to the first article thus:

1. It seems that presumption, which is a sin against the Holy Spirit, does not rely on God, but on one's own power. Sin is the greater, the lesser is the power in which one puts too much trust, and the power of man is less than the power of God. Hence one who presumes on the power of man is guilty of a greater sin than one who presumes on the power of God. Now sin against the Holy Spirit is the gravest of all sins. It follows that presumption, which is said to be a kind of sin against the Holy Spirit, relies on the power of man rather than on the power of God.

2. Again, other sins arise out of sin against the Holy Spirit. For sin against the Holy Spirit is called malice, [68] and through malice a man sins. Now it seems that other sins arise out of the presumption with which a man presumes on himself, rather than out of the presumption with which he presumes on God. For Augustine makes it clear that love of oneself is the beginning of sins (14 De Civ. Dei.28). It appears, therefore, that the presumption which is a sin against the Holy Spirit relies especially on the power of man.

3. Again, sin is due to turning inordinately to changeable good. Now presumption is a sin. It is therefore due to turning to the power of a man, which is a changeable good, rather than to turning to the power of God, which is an unchangeable good.

On the other hand: by presumption one despises the divine justice which punishes sinners, just as by despair one despises the divine mercy on which hope relies. Now justice is in God, just as mercy is in God. Presumption therefore consists in turning to God in an inordinate manner, just as despair consists in turning away from him.

I answer: presumption seems to imply immoderate hope. The object of hope is a good which is arduous and yet possible, but there are two ways in which a thing may be possible for a man. It may be possible for him through his own power, and it may be possible only through the power of God. Now in either case there can be presumption through immoderate hope. The hope whereby one relies on one's own power is presumptuous, if one aims at a good beyond one's capacity as if it were possible for one to attain it, after the manner referred to in Judith 6:15 (Vulgate): "Thou humblest those that presume of themselves." Such presumption is opposed to the virtue of magnanimity, which holds to the mean in hope of this kind. But hope whereby one relies on the power of God can also be presumptuous through immoderation, if one looks for some good thing as if it were possible through the divine power and mercy, when it is not possible. It would be presumptuous, for example, for a man to hope to obtain pardon without penitence, or glory without merit. Such presumption is indeed a kind of sin against the Holy Spirit, since one who so presumes takes away or despises the aid whereby the Holy Spirit calls him back from sin.

On the first point: as we said in Q.20, Art.3, and in 12ae, Q.73, Art.3, a sin against God is more serious than other sins, owing to its kind. The presumption with which one relies on God in an inordinate manner is therefore a more serious sin than the presumption with which one relies on one's own power. To rely on the divine power for the purpose of obtaining what it is unbecoming for God to give is to deprecate the divine power, and it is obvious that one who deprecates the power of God sins more seriously than one who exalts his own power more than he ought.

On the second point: the presumption with which one presumes on God in an inordinate manner includes the love of oneself whereby one inordinately desires one's own good. For when we desire something excessively, we readily think that it is possible through others, when it is not so.

On the third point: presumption on the mercy of God includes turning to changeable good, in so far as it is the outcome of inordinate desire for one's own good. It also includes turning away from unchangeable good, in so far as it attributes to the divine power what is unbecoming to it. This means that a man turns away from the divine power.

[68] To sin through malice is to sin against the Holy Spirit when it involves rejection, through contempt, of the protection from the choice of evil which is the effect of the Holy Spirit. (22ae, Q. 14, Art. 1).