Earthly example of Christ’s relationship with the church. God recognizes marriage as a covenant representative of his covenant with the church.
“Husbands, love your wives, just as Christ also loved the church and gave Himself for her, that He might sanctify and cleanse her with the washing of water by the word, that He might present her to Himself a glorious church, not having spot or wrinkle or any such thing, but that she should be holy and without blemish. So husbands ought to love their own wives as their own bodies; he who loves his wife loves himself. For no one ever hated his own flesh, but nourishes and cherishes it, just as the Lord does the church.” (Ephesians 5:25-29)