"I pray that God will send you the Spirit," Paul writes to the Ephesians.
Here's what the Spirit does for the church: enlightens the eyes of your heart--that is, helps you to catch on to what God intends for you to be doing and what God has already done for you.
To these early Christians as they began to form congregations and missions, he is emphasizing power and what power is to be used for.
To these Christians adjusting to their life after the crucifixion of Jesus, he writes of the power available to them through God. God put this power to work in Christ and has made him the head of the church. The church is the body of Christ, "the fullness of him who fills all in all."
As I regularly do, I have been reading Boring & Craddock's People's New Testament Commentary. And, as I regularly am, I am glad that I do. For example,here's their discussion of the phrase, "glorious inheritance":
The phrase refers to God's inheritance, not the believers'. In Old Testament theology, Israel as God's chosen people is often called God's inheritance (Deut 4:20; 9:26, 29; 2 Sam 21:3; 1 Kings 8:51, 53; Ps 28:9; 33:12; 68:9; 78:62, 71; 94:14; 106:5, 4-; Isa 19:25; 47:6; 63:17; Jer 10:16; 51:19). For the author of Ephesians, to be in the church is to be incorporated into the continuing people of God, Israel (2:11-12).