On Perpetual Virginity and the Term “Firstborn”

Luke 2:7 And she gave birth to her firstborn Son…

St. Cyril of Alexandria ca. 376-444

In what sense then her firstborn? By firstborn she here means, not the first among several brethren, but one who was both her first and only son: for some such sense as (his exists among the significations of “firstborn.” For sometimes also the Scripture calls that the first which is the only one; as “I am God, the First, and with Me there is no other.” To shew then that the Virgin did not bring forth a mere man, there is added the word firstborn; for as she continued to be a virgin, she had no other son but Him Who is of the Father: concerning Whom God the Father also proclaims by the voice of David, “And I will set Him Firstborn high among the kings of the earth.” Of Him also the all-wise Paul makes mention, saying, “But when He brought the First-begotten into the world, He saith, And let all the angels of God worship Him.” How then did He enter into the world? For He is separate from it, not so much in respect of place as of nature; for it is in nature that He differs from the inhabitants of the world: but He entered into it by being made man, and becoming a portion of it by the Incarnation. For though He is the Only-begotten as regards His divinity, yet as having become our brother, He has also the name of Firstborn; that, being made the first-fruits as it were of the adoption of men, He might; make us also the sons of God. (Sermon 1: Luke 2:1-7)