Christological Decree of the Council of Rome (AD 680)

We acknowledge that one and the same our Lord Jesus Christ, the only begotten Son of God, from two and in two substances subsists, unconfusedly without change, indivisibly, inseparably, never the difference of natures destroyed on account of the union, but rather the property of each nature preserved and concurring in one person and in one subsistence; not shared or divided in a duality of persons, nor fused into one composite nature; but we acknowledge, even after the subsistential union, one and the same only begotten Son, the Word God, our Lord Jesus Christ, neither each in a different way, nor the one and the other, but the very same in two natures, that is, in the Godhead and in the humanity, because neither has the Word been changed into the nature of the flesh, nor has the flesh been transformed into the nature of the Word; for each remains what by nature it was; indeed in contemplation alone [sola contemplatione] do we discern a difference of the united natures in that from which unfusedly, inseparably, and incommutably it was composed; for one from both and each through one, because at the same time there are present both the dignity of the Godhead and the humility of the flesh, each nature, even after the union, preserving without defect its own property, "and each form doing with the mutual participation of the other what it holds as its own; the Word doing what is of the Word, and the flesh accomplishing what is of the flesh, the one of which shines forth in miracles, the other submits to injuries." Thus, it follows that as we truly confess that He has two natures or substances, that is, the Godhead and the humanity, unfusedly, indivisibly, incommutably, so also He has both two natural wills and two natural operations [duas naturales operationes], since the rule of piety instructs us that perfect God and perfect man is one and the same Lord Jesus Christ, because it is shown that the apostolic and evangelical tradition and the teaching of the holy Fathers, whom the holy, apostolic, and Catholic Church and the venerable Synods accept, have taught us this.