He is a Christian ... - Pelagius

Nothing impossible has been commanded by the God of justice and majesty. ... Why do we indulge in pointless evasions, advancing the frailty of our own nature as an objection to the one who commands us? No one knows better the true measure of our strength than he who has given it to us nor does anyone understand better how much we are able to do than he who has given us this very capacity of ours to be able; nor has he who is just wished to command anything impossible or he who is good intended to condemn a man for doing what he could not avoid doing.

It was because God wished to bestow on the rational creature the gift of doing good of his own free will and the capacity to exercise free choice, by implanting in man the possibility of choosing either alternative. ... He could not claim to possess the good of his own volition, unless he was the kind of creature that could also have possessed evil. Our most excellent creator wished us to be able to do either but actually to do only one, that is, good, which he also commanded, giving us the capacity to do evil only so that we might do His will by exercising our own. That being so, this very capacity to do evil is also good – good, I say, because it makes the good part better by making it voluntary and independent, not bound by necessity but free to decide for itself.

Yet we do not defend the good of nature to such an extent that we claim that it cannot do evil, since we undoubtedly declare also that it is capable of good and evil; we merely try to protect it from an unjust charge, so that we may not seem to be forced to do evil through a fault of our nature, when, in fact, we do neither good nor evil without the exercise of our will and always have the freedom to do one of the two, being always able to do either.