When we talk about the Apostolic office, it touches on God's creation, the state of the world after the fall, God's redemptive work, and the Church. It's not to do with cultural or political issues.
The twelve apostles correspond to the twelve patriarchs with their twelve tribes of Israel. That is, Israel, by divine will, were to bring forth the Messiah, our Lord Jesus Christ, and He is our cornerstone, with the apostles, by divine will, as the foundation of our faith. So, the Church is built upon the teachings and examples of the apostles and Christ - that is, the very Word of God.
The word "apostle" can be understood to mean "sent" or "the one who is sent". In Christian usage, this means one who is sent by God; a messenger or ambassador. In the NT, "apostle" is used in a broad sense to mean anyone who rightly proclaims the Gospel in God's name, sent by the Church. This would be evangelists, missionaries, priests/pastors and deacons in a broad sense. However, in its narrow sense, it typically means the Twelve. "Apostle" in this narrow sense comes with very clear conditions as found in Acts 1:21-25. That is, they (1) had to be with Christ in His entire earthly ministry, from the beginning of the baptism of John. (2) They had to be eyewitnesses of Christ's resurrection. (3) They had to be divinely sent.
Now, there has been some controversy about how Paul fits into the role of an apostle, given that the office specified above in its narrow sense would have excluded Paul. Some have suggested that Paul was meant to take the place of Judas. Personally, I believe that this situation is comparable to the order of the Levities and the order of Melchizedek - that is, the priesthood belongs to Israel, but at the same time it is outside of it, in the person of Christ. Or in other words, God is the God of Israel, but He is also the God of us, the gentiles. I'm of the belief that this is reflected in the Twelve and Paul, as Paul is the apostle to us, the gentiles. So, Paul is the least but the greatest apostle at the same time.
The apostles (and the Levitical priesthood, and Jesus Christ, for that matter) were men, not for cultural reasons. Paul explains this to Timothy when he talks about the pastoral office, which is an extension of the apostolic office. That is, the priest/pastor is to speak the same message the apostles spoke: the full counsel of God's Word; God's Law and Gospel. In 1 Timothy 2 we have Paul's famous line: "I do not permit a woman to teach or to exercise authority over a man; rather, she is to remain quiet." Many in our day sadly take this verse out of context and speculate why Paul said this, and conclude that it was for local and cultural reasons. But Paul in the very next verse explains why. He says: "For Adam was formed first, then Eve; and Adam was not deceived, but the woman was deceived and became a transgressor. Yet she will be saved through childbearing—if they continue in faith and love and holiness, with self-control." We can be assured that this is not for cultural reasons, but deeply theological. It has to do with two things: (1) God's creation before the fall, and (2) the relationship between man and woman after the fall, as a consequence of our sin.
God created man and woman of equal value but opposite. The Hebrew word "ishah", "woman", means something to the effect of "same but opposite", "counterpart" or "helper". Perhaps the best way to think of it is that man and woman are both made in the image of God and they are made complementary to one another. Woman is not of lesser value or of lower status than man. Yet, man was made from God, and woman was made from man. There’s a beautiful picture of how man is sacrificed to give life to the woman. It’s like Christ giving up Himself for His bride, the Church. Sacrifice is in the very heart of marriage and it’s on the part of man. After the fall, however, the relationship between God, man and woman is broken. Because of sin, mankind no longer loves, fears or trusts in God. To the woman, God said: "Your desire shall be for your husband, and he shall rule over you." To man, God said: "Because you have listened to the voice of your wife and have eaten of the tree of which I commanded you, ‘You shall not eat of it’, cursed is the ground because of you; in pain you shall eat of it all the days of your life"
For this reason, then, apostles were men: In a pre-fall sense, because it reflects God's institution of family and His relationship with us. And in a post-fall sense, because after the fall, woman is subject to man. However, the latter is temporary and conquered by the person and works of Jesus Christ.
The bottom line is, that all the apostles are men is not for cultural reasons nor by accident, but it serves to point to God's grace. We can understand this if we properly understand God's design of man and woman, and Christ as the bridegroom and the Church as His bride. Simply speaking, everything God does He works for the good of those who are called according to His purpose.
