The reading is from St. Paul's Letter to the Ephesians 3:8-21

Brethren, to me, though I am the very least of all the saints, this grace was given, to preach to the Gentiles the unsearchable riches of Christ, and to make all men see what is the plan of the mystery hidden for ages in God who created all things; that through the church the manifold wisdom of God might now be made known to the principalities and powers in the heavenly places. This was according to the eternal purpose which he has realized in Christ Jesus our Lord, in whom we have boldness and confidence of access through our faith in him. So l ask you not to lose heart over what I am suffering for you, which is your glory. For this reason I bow my knees before the Father of our Lord Jesus Christ, from whom every family in heaven and on earth is named, that according to the riches of his glory he may grant you to be strengthened with might through his Spirit in the inner man, and that Christ may dwell in your hearts through faith, that you, being rooted and grounded in love, may have power to comprehend with all the saints what is the breadth and length and height and depth, and to know the love of Christ which surpasses knowledge, that you may be filled with the fulness of God. Now to him who by the power at work within us is able to do far more abundantly than all that we ask or think, to him be glory in the church and in Christ Jesus to all generations, for ever and ever. Amen.