Perpetual virginity of Mary

There is no explicit mention of Mary's perpetual virginity, for or against, in the New Testament (though her virginity before and in regards to Jesus' conception is well attested).[26] Nonetheless, certain biblical passages have been employed in more complicated theological argumentation.

At the Annunciation (Luke 1:34), when Mary was told by an angel that she will conceive, she responded: "How shall this be done, for I know not man." Gregory of Nyssa understood this in support of the view that Mary had taken a lifelong vow of virginity, even in through marriage:

For if Joseph had taken her to be his wife, for the purpose of having children, why would she have wondered at the announcement of maternity, since she herself would have accepted becoming a mother according to the law of nature?[27]
This argument had precedent in traditions witnessed by the early apocrypha, such as the early second century Protoevangelium of James, which asserted that Mary's mother, Anne, gave Mary as a "virgin of the Lord" in service in the Temple, and that Joseph, a widower, was to serve as her guardian (legal protections for women depended on their having a male protector: father, brother, or, failing that, a husband).[28] This may correlate to the Bible’s presentation that women devoted to perpetual service at the temple was contemporary to Mary's lifetime, and had been practiced for centuries.[29]

In typological argumentation, Ezekiel 44:2 has been used in support of the doctrine. The passage reads: ‘The Lord said to me, “This gate is to remain shut. It must not be opened; no one may enter through it. It is to remain shut because the Lord, the God of Israel, has entered through it.”’ Jerome interpreted this passage as referring, typologically, to Mary:

Only Christ opened the closed doors of the virginal womb, which continued to remain closed, however. This is the closed eastern gate, through which only the high priest may enter and exit and which is nevertheless always closed.[30]
This argumentation was repeated, not only be later Catholic theologians, but by the magisterial Protestant Reformers as well,[31] in support of the doctrine.

The New Testament references Jesus' adelphoi,[32] which can mean either "brothers" or "kinsfolk".[33] The early second century Protoevangelium of James presented these adelphoi as Joseph’s children from a previous marriage, stating that Joseph married Mary after he had become a widower. Thus, these adelphoi were Jesus’ half-brothers. Victorinus argued that the adelphoi were merely kinsfolk, an view repeated by Jerome.[34] Tertullian interpreted these passages as referring to Jesus’ siblings from both Joseph and Mary, and rejected the doctrine of Mary’s perpetual virginity.[35]

Matthew 1:25, states that Jesus was Mary's "firstborn son" and that Joseph "had no marital relations with her until (εως) she had borne a son." Some argue that this passage implies that Mary and Joseph had customary marital relations after the birth of Jesus.