De natura et gratia libri III, cum Apologia contra Catharinum

It declares furthermore that the beginning of justification itself in adults must be taken from the prevenient grace of God through Jesus Christ, that is, from his calling: by which they are called when none of their merits exist, so that those who had turned away from God through sins may, through his arousing and assisting grace, be disposed to convert themselves to their own justification by freely assenting to and cooperating with that same grace, in such a way that, when God touches the heart of man through the illumination of the Holy Spirit, neither does man himself do nothing at all, receiving that inspiration, since he can also reject it, nor yet can he move toward justice before him without the grace of God, but can do so by his own free will. Hence, when it is said in the sacred writings, Turn to me, and I will turn to you, we are reminded of our liberty, when we answer, Turn us, O Lord, to you, and we shall be turned. We confess that we are prevented by the grace of God.