Second Council of Constantinople, Capitulum IX

If anyone shall take the expression, Christ ought to be worshipped in his two natures, in the sense that he wishes to introduce thus two adorations, the one in special relation to God the Word and the other as pertaining to the man; or if anyone to get rid of the flesh, [that is of the humanity of Christ,] or to mix together the divinity and the humanity, shall speak monstrously of one only nature or essence (φύσιν ἤγουν οὐσίαν) of the united (natures), and so worship Christ, and does not venerate, by one adoration, God the Word made man, together with his flesh, as the Holy Church has taught from the beginning:  let him be anathema.

Translation: Henry R. Percival, The Seven Ecumenical Councils, NPNF II.14 (1900), via CCEL.