Nicene and Post-Nicene Fathers: Series I/Volume V/Against Two Letters of the Pelagians/Book IV/Chapter 12

Chapter 12 [VI.]—Of the Praise of Free Will.

Moreover, that, in opposition to the Manicheans, they praise free will, making use of the prophetic testimony, “If ye shall be willing and will hear me, ye shall eat what is good in the land; but if ye shall be unwilling and will not hear me, the sword shall consume you:” what advantage is this to them, when, indeed, it is not so much against the Manicheans that they are maintaining, as against the catholics that they are extolling, free will? For they wish what is said, “If ye be willing and will hear me,” to be so understood, as if in the preceding will itself were the merit of the grace that follows; and thus grace were no more grace, seeing that it is not free when it is rendered as a debt. But if they should so understand what is written, “If ye be willing,” as to confess that He prepares even that good will itself of whom it is written, “The will is prepared by the Lord,” they would use this testimony as catholics, and not only would overcome the ancient heresy of the Manicheans, but would not found the new one of the Pelagians.