How does Paul describe the love Christ has for the Church?
"Husbands, love your wives, just as Christ also loved the church and gave Himself for her" (Ephesians 5:25 Ephesians 5:25Husbands, love your wives, even as Christ also loved the church, and gave himself for it;
American King James Version×). Jesus loves the Church as a man anticipating marriage to the woman of his dreams. He was willing to give His life to save hers.
What will the Bride wear to the wedding when Christ returns to rule the earth?
"And I heard, as it were, the voice of a great multitude, as the sound of many waters and as the sound of mighty thunderings, saying, 'Alleluia! For the Lord God Omnipotent reigns! Let us be glad and rejoice and give Him glory, for the marriage of the Lamb has come, and His wife has made herself ready.' And to her it was granted to be arrayed in fine linen, clean and bright, for the fine linen is the righteous acts of the saints" (Revelation 19:6-8 Revelation 19:6-8  And I heard as it were the voice of a great multitude, and as the voice of many waters, and as the voice of mighty thunder, saying, Alleluia: for the Lord God omnipotent reigns.
 Let us be glad and rejoice, and give honor to him: for the marriage of the Lamb is come, and his wife has made herself ready.
 And to her was granted that she should be arrayed in fine linen, clean and white: for the fine linen is the righteousness of saints.
American King James Version×).
The Church will have made herself spiritually ready for this wedding. She is represented as wearing a beautiful wedding dress, which, in fact, represents her righteous acts. What is righteousness in God's eyes? Psalms 119:172 Psalms 119:172My tongue shall speak of your word: for all your commandments are righteousness.
American King James Version×defines it for us: "My tongue shall speak of Your word, for all Your commandments are righteousness." Righteous acts include obedience to God's commandments and continually striving to follow Jesus' perfect example.
How does Christ prepare the Church for that majestic wedding?
"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" (Ephesians 5:25-27 Ephesians 5:25-27  Husbands, love your wives, even as Christ also loved the church, and gave himself for it;
 That he might sanctify and cleanse it with the washing of water by the word,
 That he might present it to himself a glorious church, not having spot, or wrinkle, or any such thing; but that it should be holy and without blemish.
American King James Version×).
The "spots" Paul refers to here are sins that tarnish the beautiful clean dress of Christ's bride-to-be. Sin—the violating of God's laws—must be washed away by Christ's sacrifice and kept away by a Christian's use of the power of the Holy Spirit to change and grow spiritually. God's Church teaches, and endeavors to live by, God's laws. It actively prepares to become the unblemished Bride of Christ.