Paul focuses on the work of Christ in the lives of His followers. In verse 1 it refers to to Christians who realize that they were once dead but now that they are follower of Christ they have a new life. They were dead because they lived in sin and followed the ways of the world.
These verses start out the best way, "But God." God has intervened and with His mercy and love He shows He is not only a God of wrath. Paul portrays the picture of us as believers being right there with Jesus at His resurrection, ascension, and enthronement. How much more of a personal relationship can there be. In verse 7 he says that "He will show us the riches of His grace in kindness towards us in Christ Jesus." The future is bright and His kindness is love in action.
These few verses best sum up the Gospel in the New Testament. Please read these verses because the Bible states it better than I can. Our God is generous, a Savior, and a Redeemer. He uses the word "faith" which is easily put as having the total openness to let God in and take control. God expresses how His plan for our lives includes a walk, a course of living.
Now Paul is not speaking just to one Christian but to a group of believers. He speaks to those who are Gentiles about how they disobeyed the covenant that Moses had made with God when it came to circumcision. By that act of disobedience they had separated themselves from God, but now by the blood of Christ are brought closer to Him. By His grace He broke the barriers between the Jews and the Gentiles and formed a union which had not been there previously.
The Gentiles were now official citizens of the area they were living in but also members of the family of God. This family was to be a structure that God could dwell in and be the cornerstone (the main support). The base of the structure were the apostles and the prophets. Together we dwell as one with Jesus right in the middle.