Which is for the same reason car thieves cannot find a police station. The facts are that,
• Marriage is described as cleaving" and becoming one. (Gn. 2:24; Mt. 19:4-6)
• Israel knew nothing of a marriage that was not consummated between two persons who could procreate, nor does the NT.
• Under the New Covenant celibacy is only advocated in the context of being single. (Mt. 19:10-12; 1Cor. 7:8)
• Paul actually instructs the married to have sexual relations, and restricts abstinence in marriage to only a period of fasting, and then to come together again. (1Cor. 7:3-5)
•Thus a marriage in which their is no "cleaving" would be a very notable, and as far as Catholicism is concerned, very important. Yet while the Holy Spirit characteristically records extraordinary exceptions to the norm among its characters, from the age of Methuselah to the strength of Samson to the number of toes of Goliath, to the diet of John the Baptist, to the supernatural transport of Phillip, to the signs of an apostle, to the singleness of Paul and Barnabas, and uncharacteristic duplicity of Peter, to the prolonged celibacy of Anna, to the sinlessness of Christ, etc., He says nothing about Mary being a perpetual virgin. And instead what He does teach weighs toward the norm.
• Except in rare instances "heōs" ("And knew her not till she had brought forth her firstborn son: and he called his name JESUS." Matthew 1:25) indicates a terminus and a change, or allowing for that..
• Instead of any teaching that Mary was a perpetual virgin, ,we have many texts which refer to Mary having other children. (Mat_12:46,48, Mat_27:56; Mar_15:40,47, Mar_16:1; Luk_24:10; Joh_19:25; Gal_1:19) Likewise Psalms 69:8 states, "I am become a stranger unto my brethren, and an alien unto my mother's children." Adelphos* (brethren) often refers to biological siblings, and while it need not do so, there is no justification for excluding it as meaning so.
• If "brothers" refers to Joseph's sons by an earlier marriage, not Jesus but Joseph's firstborn would have been legal heir to David's throne. The second theory — that "brothers" refers to sons of a sister of Mary also name "Mary" — faces the unlikelihood of two sisters having the same name. — D. A. Carson, Matthew in The Expositor's Bible Commentary, volume 8 (Zondervan, 1984).
Jason Engwer states , Luke uses the word "supposedly" to describe Jesus' relationship with Joseph (Luke 3:23), but doesn't use any such terminology to describe Jesus' relationship with His brothers and sisters, but repeatedly chooses the term "brother" to describe Jesus' siblings, even though he understood the difference between a "relative" and a "brother", even distinguishing between the two within a single sentence. (Luke 21:16).
• There is simply no need for Mary to be a perpetual virgin, unless martial relations are sinful or necessarily denoting inferior virtue, as some CFs erroneously held , contra. Heb. 13:4)
If there is any purely “human” tradition here, then, it is the denial of the perpetual virginity of Mary, since it originated (mostly) some 1700 years after the initial apostolic deposit: just as all heresies are much later corruptions. The earliest Church fathers know of no such thing. '
More propaganda. Besides the reality that it is estimated we only have a small portion of all that so-called church "fathers" wrote,
Basil stated that the view that Mary had other children after Jesus "was widely held and, though not accepted by himself, was not incompatible with orthodoxy" (J.N.D. Kelly, Early Christian Doctrines [San Francisco, California: HarperCollins Publishers, 1978], p. 495).
As Engwer also notes, Irenaeus refers to Mary giving birth to Jesus when she was "as yet a virgin" (Against Heresies, 3:21:10). Irenaeus compares Mary's being a virgin at the time of Jesus' birth to the ground being "as yet virgin" before it was tilled by mankind. The ground thereafter ceased to be virgin, according to Irenaeus, when it was tilled. The implication is that Mary also ceased to be a virgin. Elsewhere, Irenaeus writes:
"To this effect they testify, saying, that before Joseph had come together with Mary, while she therefore remained in virginity, 'she was found with child of the Holy Ghost;'" (Against Heresies, 3:21:4)
Tertullian comments:
Tertullian: "...indeed it was a virgin, about to marry once for all after her delivery, who gave birth to Christ, in order that each title of sanctity might be fulfilled in Christ's parentage, by means of a mother who was both virgin, and wife of one husband." (On Monogamy, 8)
To marry after she brought forth Christ denotes consummation, the formal expression of marriage, (Mt. 19:5) as it is certain Joseph took Mary to wife before the Lord was born, but "knew her not till she had brought forth her firstborn son." (Mt. 1:24,25) And in so doing Tertullian sees Mary as representative of both ideals, of continence and monogamy.
1 Corinthians 7:5
That’s an excellent point and a fact that would have had to been dealt with in scripture if it had been different. Jesus was obviously the first born of Joseph in order to inherit the throne of David.