What has Les observed about brides at weddings?
He has observed that after attending many weddings over the years, he has never seen a bride who was not attractive, even if she was otherwise plain; once she puts on the wedding gown, she is so attractive. This matches the picture of the Body of Christ as a white-clad Bride.
Les explains that the husband-and-bride analogy in Ephesians 5 is tied to Christ as the head of the Church. He says he and Iris agree, and after many weddings he has never seen a bride who wasn't attractive, regardless of whether she may have been a more or less plain girl otherwise; when she puts on the wedding gown, she is so attractive. This is exactly the picture God is drawing: the Body of Christ as the Bride, white and clean, without wrinkle and without blemish. He then returns to the physical analogy of husband and wife in verse 28.