Origen — On First Principles 3.1.1

Since the church’s proclamation includes the word about God’s just judgment — and those who trust it are called to live well and flee sin in every way, agreeing that what deserves praise or blame is in our power — let us also treat briefly of self-determination (τὸ αὐτεξούσιον), a most necessary question.

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Of things that move, some have the cause of motion in themselves; others are moved only from outside. Wood and stones are moved only from outside. Animals and plants have the cause in themselves. Rational living beings also have reason, which judges the impressions, rejecting some and accepting others, so that the creature may be led by them. We choose the fine and turn from the shameful — and are praiseworthy or blameworthy accordingly. What falls on us from outside is not in our power; judging how to use what has happened is the work of the reason in us.