This is a great mystery, but I speak concerning Christ and the church. (Ephesians 5:32)

Today’s big question: what is this mystery, and why is it great?

Today’s passage speaks of a mystery—a hidden thing. In the previous verses, Paul wrote about the correlation between the husband and wife with Christ and the church. The relationship of a husband and wife is a small example of the union between Christ and the church. However, there is so much more to know about the relationship of Christ with believers, and Paul clearly presented this fact by proclaiming the mystery of Christ and the church.

In Matthew 19:4–5, Jesus laid out the foundation of marriage by starting in Genesis and pointing out the fact and God created a male and a female. In fact, Paul referenced what Jesus said in Ephesians 5:31. Genesis is also the foundation for understanding why we need a Savior who will unify believers to Himself. Sin came through the first Adam, but through the last Adam came redemption from our sin.

Moreover, it is through the union of Adam and Eve that the Savior would eventually come down in human form: “And I will put enmity between you and the woman, and between your seed and her Seed; He shall bruise your head, and you shall bruise His heel” (Genesis 3:15). Through their marriage came Eve’s Seed, Jesus—the One whose work created the union between Himself and the church.

The message of salvation is simple (John 3:16), yet understanding the details is difficult to comprehend. Why did God love us so much that He would save sinners—creatures that have rebelled against the Creator—such as you and I? Though we may not fully understand why God planned everything the way He did, our response to such love should be to praise and glorify Him.

A union between a husband and wife is not easy—you have to work at it. Even after marriage, there is still so much to learn about your spouse. In comparison, we will never learn everything there is to know about Jesus. He is all-knowing, and we are finite beings. We will continually learn about Jesus—even in heaven.

While we are still on this earth, we merely touch the surface of the union we have with Christ. Since we are limited in our understanding, we cannot fully understand the union of Christ and the church. We know nothing compared to what God knows. That is why it is crucial to be humble and loving when it comes to one’s relationship with Christ and with one’s spouse.  http://www.answersingenesis.org/articles/2011/01/27/what-is-this-mystery