ulgentius says (De Dupl. Praedest. i, 19): "God
does not punish what He causes." Now God punishes the hardened heart,
according to Ecclus. 3:27: "A hard heart shall fear evil at the
last." Therefore God is not the cause of hardness of heart.

Obj. 3: Further, the same effect is not put down to contrary causes.
But the cause of spiritual blindness is said to be the malice of man,
according to Wis. 2:21: "For their own malice blinded them," and
again, according to 2 Cor. 4:4: "The god of this world hath blinded
the minds of unbelievers": which causes seem to be opposed to God.
Therefore God is not the cause of spiritual blindness and hardness of
heart.

_On the contrary,_ It is written (Isa. 6:10): "Blind the heart of
this people, and make their ears heavy," and Rom. 9:18: "He hath
mercy on whom He will, and whom He will He hardeneth."

_I answer that,_ Spiritual blindness and hardness of heart imply two
things. One is the movement of the human mind in cleaving to evil,
and turning away from the Divine light; and as regards this, God is
not the cause of spiritual blindness and hardness of heart, just as
He is not the cause of sin. The other thing is the withdrawal of
grace, the result of which is that the mind is not enlightened by God
to see aright, and man's heart is not softened to live aright; and as
regards this God is the cause of spiritual blindness and hardness of
heart.

Now we must consider that God is the universal cause of the
enlightening of souls, according to John 1:9: "That was the true
light which enlighteneth every man that cometh into this world," even
as the sun is the universal cause of the enlightening of bodies,
though not in the same way; for the sun enlightens by necessity of
nature, whereas God works freely, through the order of His wisdom.
Now although the sun, so far as it is concerned, enlightens all
bodies, yet if it be encountered by an obstacle in a body, it leaves
it in darkness, as happens to a house whose window-shutters are
closed, although the sun is in no way the cause of the house being
darkened, since it does not act of its own accord in failing to light
up the interior of the house; and the cause of this is the person who
closed the shutters. On the other hand, God, of His own accord,
withholds His grace from those in whom He finds an obstacle: so that
the cause of grace being withheld is not only the man who raises an
obstacle to grace; but God, Who, of His own accord, withho