To speak of the nuptial meaning of the body, means that the very design of our body orients us toward a marital relationship. The man is meant for the woman, the woman for the man. And in this complementary relationship which we call marriage, there is the fruitfulness of children. In effect, our body says to us, "You were made for another who will complement and complete you, making your love fruitful." 
 
This is also an image for the spiritual life, wherein God speaks of his relationship to his people in marital imagery. Israel was frequently described as God's bride. In the New Testament, Jesus is the Groom and his Church is his bride. The Church and her members are called to relate to the Lord, to be completed by him and complemented by him such that their love bears fruit. 
 
The sacrament of Holy Matrimony is also a sign of God's relationship to his people, he the groom, we the bride. Even celibates manifest the nuptial meaning of the human person. A priest is not a bachelor. He has a bride, the Church. Religious sisters also manifest a marital relationship, where Jesus is the Groom, they are his bride. 
 
To speak, therefore, of the nuptial meaning of the body, is to insist that the sexual distinctions of male and female are not merely arbitrary physical aspects. Rather, they bespeak deeper, spiritual realities that we must learn to appreciate, and respect. Men and women are different, and manifest different aspects of God's relationship. Women manifest the glory of the Church as bride. Men manifest the glory of Christ as groom. 
 
In terms of the priesthood, this is important, because Christ in his humanity, is not simply male, he is groom, and the sacred liturgy is a wedding feast; Christ the groom, intimately with his bride the Church. 
 
Thus, your pastor is invoking rich theological teaching, which helps to explain one reason why Christ chose only men for the priesthood.

When we speak of the age of a particular Book in the Bible we can speak about its age in terms of the events it describes, or of the likely date it was put into the written form we have today. Usually when scholars speak of the age of a Book they refer to the time of its appearance in final written form. And in this sense, it is largely accepted that the First Letter to the Thessalonians is probably the oldest book, the first of St. Paul’s letters, and written between 51‐52 AD. 
 
The writing of a letter in the New Testament was a fairly straight‐forward process and, while St. Paul and others may have had made some final edits, or even a second draft, it is likely he dictated it to a scribe, who wrote it and then had it sent within a matter of days. Other copies may also have been made and circulated. 
 
The emergence of the Gospels in written form was a much more complicated process. And while the events they detail are older (from the early 30s AD), the writing out of these events went through several stages. 
 
Obviously the first stage of the Gospels was the actual events themselves, the words and deeds of Jesus. But it will be noted that Jesus did not write a book, or even say to the Apostles, “Go write a book.” Rather, he sent them to preach, teach, and baptize disciples into the life of his Body, the Church. 
 
Thus, the second stage was the oral stage wherein the Apostles went forth proclaiming what Jesus taught and did and who Jesus is. During this time the teachings began to be written by scribes, collected and circulated. 
 
And thus, we begin to see the written stage. The idea that Matthew or John just sat down and wrote the gospel is probably inaccurate. Recall that most people could not write in the ancient world. Scribes and others acted as secretaries for the author who helped refine and edit the final product. Some think that Mark was Peter’s assistant and scribe. 
 
Gradually the gospels were collected and edited in what came to be their final form, as we know them. The exact dates and order of their final form are hotly debated topics among scholars. However, it is safe to say that the four gospels took their final form between 60 and 90 AD, some time after St. Paul had sent his letters.