Regardless of the interpretation of “brethren,” which is important, I’d like my Roman Catholic friends to consider that if Mary and Joseph never consummated their marriage then they weren’t really married.
And if the one was denying sex to the other, either way, they were actually sinning.
“I’d like my Roman Catholic friends to consider that if Mary and Joseph never consummated their marriage then they weren’t really married.”
Exactly. Their marriage would have been fraudulent.
Biblically, Mary fulfilled prophecy by conceiving and giving birth to Jesus BEFORE her marriage to Joseph was consummated. Matthew quotes Isaiah 7:14 which contains this Messianic sign:
Matthew 1:23, 25
“Behold, the virgin shall be with child, and bear a Son, and they shall call His name Immanuel,” which is translated, “God with us”...
And [Joseph] did not know her [Mary] till she had brought forth her firstborn Son. And he called His name Jesus.
The word “till”, meaning until, is found in Catholic Bibles, not just Protestant. It is from the Greek “heos” which is a preposition meaning “as far as, up to, as much as, until.”
Look what Paul, an apostle, instructed regarding abstinence in marriage:
1 Corinthians 7:5
Do not deprive one another except with consent for a time, that you may give yourselves to fasting and prayer; and come together again so that Satan does not tempt you because of your lack of self-control.
This shows that a godly marriage must include physical intimacy. Any abstinence should be temporary and for a good reason.
Matthew 1:20
But while he thought about these things, behold, an angel of the Lord appeared to him in a dream, saying, “Joseph, son of David, do not be afraid to take to you Mary your wife, for that which is conceived in her is of the Holy Spirit.”
Joseph is instructed by God to “take” Mary as his wife. The only reason for their abstinence was to fulfill the Biblical prophecy cited. Beyond this abstinence would have been contrary to the very nature and design of marriage by God. It would have served no purpose whatsoever, except as a tool of the Devil to cause them to sin and as an exercise of self-righteous pride.
Catholic clergy and other advocates want to argue over this issue because they put tradition above the word of God and exalt Mary beyond measure. Though the images they bow to and offer prayers, incense, and flowers to in idolatry is not the real Mary but an impostor spirit cleverly designed by the forces of darkness to lead astray potential followers of Christ within their false religion away from Christ into idol worship.
The central focus of the Bible is Christ Jesus, not Mary or other persons who have achieved some “sainthood” unique to them and not others with faith in the Lord Jesus.
Colossians 2:8-10
Beware lest anyone cheat you through philosophy and empty deceit, according to the tradition of men, according to the basic principles of the world, and not according to Christ. For in Him dwells all the fullness of the Godhead bodily; and you are complete in Him, who is the head of all principality and power.