Cyril begins the Scholia with the name given by the prophet Isaiah: Emmanuel, which is translated, 'God with us'. The name is the doctrine in compact form. The One who is now with us is God, and the manner of His being with us is by having taken our nature to Himself. To say Emmanuel is to confess in a single word the two truths the heretics divide: that He who is with us is truly God, and that He is truly with us in our flesh.

Cyril notes that the Septuagint, the version received in the Church, names the Child 'God with us' before His birth. The name is not given on account of moral indwelling; it is given to the Person who is being conceived in the Virgin. The prophet's word forbids the Nestorian reading from the very beginning.

Cyril gives the eternal half of the doctrine first. The Word is from the Father, of one essence with Him, before all ages. He is not made; He is not adopted; He is not a creature elevated to divine status. He is what the Father is, except that He is Son and the Father is Father. The relations differ; the essence is one.

This eternal Sonship is the precondition of the Incarnation. The One who takes flesh in the Virgin's womb is not a new person who comes into being there; He is the eternal Son who, without ceasing to be what He was, becomes what He was not.

Cyril names the flesh of Christ as the Word's own flesh: not a flesh externally connected to Him, not a man with whom He has come to dwell, but the flesh which He has made His own by personal union. The flesh is animated by a rational soul, complete in everything proper to humanity, taken in its entirety from the Virgin without seed.

Cyril is careful: in saying that the flesh is the Word's own, he does not mean that the flesh becomes divine in essence. The flesh remains flesh; the divinity remains divinity. The union is in the Person of the Word, who, having made the flesh His own, does in it everything that He does, divine and human alike.

Cyril sets out the rule of the communication of idioms: what is proper to either nature in Christ may be said of the one Person, because the one Person is the subject of both natures. The Virgin bears in the flesh the One who is God; the immortal God dies on the Cross in His own flesh; the One who hungers in the wilderness is the One who feeds creation. Each of these statements is true, because the subject of both verbs is the same Person.

Cyril warns against the misuse of the rule. To say that God died in the flesh is not to say that the divine nature suffered. To say that Mary bore God is not to say that her flesh contributed to the divinity. The rule does not mix the natures; it names the one Person who holds them both.