It is obvious that Mary had children after Jesus was born. As long as Jesus was conceived by the Holy Spirit, why was it necessary that Mary have no previous children? I am not asking why it was necessary that Jesus be conceived by the Holy Spirit—I understand that. I guess my question is, Why would it matter that Mary had other children first, as long as Jesus was conceived by the Spirit?
I agree with you that from what is said in Scripture, it appears to be "obvious that Mary had children after Jesus was born. " Take, for example, this passage:
2When the Sabbath came, he [Jesus] began to teach in the synagogue, and many who heard him were amazed. "Where did this man get these things?" they asked. "What's this wisdom that has been given him, that he even does miracles! 3Isn't this the carpenter? Isn't this Mary's son and the brother of James, Joseph, Judas and Simon? Aren't his sisters here with us?".... (Mark 6:2-3, New International Version)
It has been argued (particularly by those who believe in the "perpetual virginity" of Mary) that the word translated "brother" (Greek "adelphos," as in "Philadelphia," "the city of brotherly love") might be taken as "cousin," but the context surely indicates that we are not talking about several households here, but one.
Incidentally, perhaps it should be noted in passing that although Jesus, James, Joseph, Judas, and Simon were all of the same household and all had Mary as their mother, Mary's husband Joseph was the physical father of James, Joseph, Judas, and Simon, but not of Jesus, who was conceived of the Holy Spirit (see Matthew 1:20; Luke 1:35). Thus, technically speaking, Jesus and his "brothers" were "half-brothers," since they only shared the same mother, but it would certainly be understandable for those in Nazareth who personally knew of the family to regard the five sons as "brothers."
Consider, also, how this passage speaks of the birth of Jesus:
22All this took place to fulfill what the Lord had said through the prophet: 23"The virgin will be with child and will give birth to a son, and they will call him 'Immanuel' which means, 'God with us'." 24When Joseph woke up, he did what the angel of the Lord had commanded him and took Mary home as his wife. 25But he had no union with her until she gave birth to a son. And he gave him the name Jesus. (Matt. 1:22-25, NIV)
The words "But he had no union with her until she gave birth to a son" certainly seem to suggest that after Mary gave birth to Jesus, Joseph did have union with her and that, having given birth to one Child, she gave birth to other children as well.
But let's get to the heart of your question: "Why was it necessary that Mary have no previous children?.... Why would it matter that Mary had other children first, as long as Jesus was conceived by the Spirit?
Here's the simple answer: It was necessary for Jesus to be born of a virgin to fulfill Isaiah's prophecy:
"Therefore the Lord himself will give you a sign: The virgin will be with child and will give birth to a son, and will call him Immanuel. (Is. 7:14, NIV)
Speaking of the birth of Christ of a virgin, Matthew (as we have already seen) says this:
22All this took place to fulfill what the Lord had said through the prophet: 23"The virgin will be with child and will give birth to a son, and they will call him Immanuel." (Matt. 1:22-23, NIV)
Although the exact meaning of the Hebrew word "'almah" in Isaiah 7:14 has been disputed (some—ignoring the context—take it as simply "young woman of marriageable age"), there is absolutely no dispute over the meaning of the Greek word "parthenos" in Matthew 1:23, which can have no other meaning than "virgin" (and Matthew 1:23 supplies us with an inspired interpretation of Isaiah 7:14).
Thus Scriptural prophecy found its fulfillment when our Savior was, in the familiar words of the Apostles' Creed, "conceived of the Holy Ghost, born of the virgin Mary."
"Questions and Answers" is a weekly feature of the OPC website. At least one new question is posted each week, so there should always be something new here for you to read. (For those who would like to look at previous questions and answers, they will continue to be available as well.)
The questions come from individuals like yourself. If you have questions about biblical and theological matters, you are invited to send them by e-mail by using the "Pose a Question" link on the OPC home page or by clicking here.
The purpose of the OPC website's "Questions and Answers" is to respond to biblical and theological questions. Matters of church discipline, disputes, or debates go beyond the scope of our work. We recommend that you present your concerns in these areas to the appropriate judicatory. In most cases this will be to a local pastor, elder, or session. We do not want the website to replace personal involvement in, or commitment to, the local, visible church.
While we will respond to every serious questioner, we are not bound to give a substantive answer to every question, should we deem the question to be beyond the scope of our purpose or our own ability to answer.
You will receive an answer by email. Please be patient as many of our respondents are busy pastors. The response to your question may take up to two weeks. Some of the questions submitted will be chosen to be posted here, along with the corresponding answers.
The answers come from individual ministers in the Orthodox Presbyterian Church expressing their own convictions and do not necessarily represent an "official" position of the Church, especially in areas where the Standards of the Church (the Scriptures and the Westminster Confession of Faith and Catechisms) are silent.
Note that the "Questions and Answers" posted on the site have been editedall personal references are removed, Scripture references may be added, and sometimes portions are expandedto make the questions and answers more useful to a larger audience.