Shared ground

Ephesians 5:31–33 treats marriage as a real union. It grounds that claim by quoting Genesis 2:24: a man leaves his parents, is joined to his wife, and the two become “one flesh.” In the flow of the paragraph, that “one flesh” language supports the idea that marriage forms a new primary bond and shared life.

The author then says this “mystery” is “great” and explains what he means: he is speaking “in regard of Christ and of the assembly.” That is an explicit shift from the human marriage statement to a larger reference point (Christ’s relationship to the church). After that, he returns to the household level and summarizes: husbands are to love their own wives as themselves, and wives are to see that they respect their husbands.

Where interpretation differs (only where needed)

What “one flesh” mainly emphasizes. Some readers treat “one flesh” as mainly referring to bodily/sexual union, with relational unity as a result. Others treat it as a whole-life union (shared identity and kinship), which includes bodily union but is not limited to it. The text itself points to both body-and-life unity by combining “joined” with “one flesh.”

How the Christ–church reference relates to marriage. Some understand v. 32 as saying marriage is primarily an illustration that helps explain Christ and the church. Others understand it as saying marriage was always meant to point beyond itself, so that Christ and the church are the deeper reality that marriage echoes. Both readings agree that the author explicitly connects Genesis 2:24 language to Christ and the church.

What “mystery” means here. Some take “mystery” to mean there was a meaning in Genesis 2:24 that was not obvious until now and is now being explained. Others take it more generally as “a profound truth,” without stressing prior hiddenness. In either case, the author explicitly says the “mystery” is “great” and ties it to Christ and the church.

Why the disagreement exists

The passage moves quickly from a human marriage text (Genesis 2:24) to a Christ-and-church reference and then back to practical marital summary. Because the author does not spell out the exact direction of the comparison (marriage → Christ, or Christ → marriage, or both), readers infer the relationship from the brief wording and the surrounding context (especially the preceding comparison to Christ’s care in 5:25–30).

What this passage clearly contributes

• Marriage is presented as a new, joined union that can be described as “one flesh.”
• Genesis 2:24 is treated as directly relevant for understanding marriage.
• The author states that the marriage-union language has a “great” significance when considered “in regard of Christ and of the assembly.”
• The paragraph ends with a compact summary of marital obligations: husbandly love “as himself” and a wife’s respect for her husband. These are the explicit closing points of the unit.