An interesting perspective on repeated words is to look at all the times purpose is expressed in Ephesians. I suspect some have been missed in this list, but it's a good start.
Ephesians 1:10 that in the dispensation of the fullness of the times He might gather together in one all things in Christ, both which are in heaven and which are on earth--in Him.
Ephesians 1:12 that we who first trusted in Christ should be to the praise of His glory.
Ephesians 1:17 that the God of our Lord Jesus Christ, the Father of glory, may give to you the spirit of wisdom and revelation in the knowledge of Him,
Ephesians 1:18 the eyes of your understanding being enlightened; that you may know what is the hope of His calling, what are the riches of the glory of His inheritance in the saints,
Ephesians 2:7 that in the ages to come He might show the exceeding riches of His grace in His kindness toward us in Christ Jesus.
Ephesians 2:10 For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.
Ephesians 2:16 and that He might reconcile them both to God in one body through the cross, thereby putting to death the enmity.
Ephesians 3:6 that the Gentiles should be fellow heirs, of the same body, and partakers of His promise in Christ through the gospel,
Ephesians 3:8 To me, who am less than the least of all the saints, this grace was given, that I should preach among the Gentiles the unsearchable riches of Christ,
Ephesians 3:10 to the intent that now the manifold wisdom of God might be made known by the church to the principalities and powers in the heavenly places,
Ephesians 3:16 that He would grant you, according to the riches of His glory, to be strengthened with might through His Spirit in the inner man,
Ephesians 3:17 that Christ may dwell in your hearts through faith; that you, being rooted and grounded in love,
Ephesians 3:19 to know the love of Christ which passes knowledge; that you may be filled with all the fullness of God.
Ephesians 4:10 He who descended is also the One who ascended far above all the heavens, that He might fill all things.)
Ephesians 4:14 that we should no longer be children, tossed to and fro and carried about with every wind of doctrine, by the trickery of men, in the cunning craftiness of deceitful plotting,
Ephesians 4:17 This I say, therefore, and testify in the Lord, that you should no longer walk as the rest of the Gentiles walk, in the futility of their mind,
Ephesians 4:22 that you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts,
Ephesians 4:24 and that you put on the new man which was created according to God, in true righteousness and holiness.
Ephesians 4:28 Let him who stole steal no longer, but rather let him labor, working with his hands what is good, that he may have something to give him who has need.
Ephesians 5:26 that He might sanctify and cleanse her with the washing of water by the word,
Ephesians 5:27 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 6:3 "that it may be well with you and you may live long on the earth."
Ephesians 6:11 Put on the whole armor of God, that you may be able to stand against the wiles of the devil.
Ephesians 6:13 Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand.
Ephesians 6:19 and for me, that utterance may be given to me, that I may open my mouth boldly to make known the mystery of the gospel,
Ephesians 6:20 for which I am an ambassador in chains; that in it I may speak boldly, as I ought to speak.
Ephesians 6:21 But that you also may know my affairs and how I am doing, Tychicus, a beloved brother and faithful minister in the Lord, will make all things known to you;
Ephesians 6:22 whom I have sent to you for this very purpose, that you may know our affairs, and that he may comfort your hearts.