Second Council of Constantinople, Capitulum VII

If anyone using the expression, “in two natures,” does not confess that our one Lord Jesus Christ has been revealed in the divinity and in the humanity, so as to designate by that expression a difference of the natures of which an ineffable union is unconfusedly made, [a union] in which neither the nature of the Word was changed into that of the flesh, nor that of the flesh into that of the Word, for each remained that it was by nature, the union being hypostatic; but shall take the expression with regard to the mystery of Christ in a sense so as to divide the parties, or recognising the two natures in the only Lord Jesus, God the Word made man, does not content himself with taking in a theoretical manner^[310] the difference of the natures which compose him, which difference is not destroyed by the union between them, for one is composed of the two and the two are in one, but shall make use of the number [two] to divide the natures or to make of them Persons properly so called:  let him be anathema.^[311]

Source edition notes

[310] I.e. “as an abstraction (τῇ θεωρίᾳ μόνῃ).”

[311] The text here is uncertain.

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