Unbeknownst to the people of Moses’ day (it was a ‘mystery’), marriage was designed by God from the beginning to be a picture or parable of the relationship between Christ and the church. Back when God was planning what marriage would be like, He planned it for this great purpose: it would give a beautiful earthly picture of the relationship that would someday come about between Christ and His church. This was not known to people for many generations, and that is why Paul can call it a ‘mystery.’ But now in the New Testament age Paul reveals this mystery, and it is amazing. This means that when Paul wanted to tell the Ephesians about marriage, he did not just hunt around for a helpful analogy and suddenly think that “Christ and the church” might be a good teaching illustration. No, it was much more fundamental than that: Paul saw that when God designed the original marriage, He already had Christ and the church in mind. This is one of God’s great purposes in marriage: to picture the relationship between Christ and His redeemed people forever! (George Knight)