“For this reason, ever since I heard about your faith in the Lord Jesus and your love for all the saints, I have not stopped giving thanks for you, remembering you in my prayer” (Ephesians 1:15-16)
It is not unusual for the Apostle Paul to open each of his letter with a prayer for the people he’s writing to. However, Ephesians is unique because he stops twice to pray (Eph. 1:15-23; 3:14-21). Both prayers are similar in that he is praying that they (and by extension us) will grasp the fullness of the mystery he’s writing about in this letter. The mystery is about Christ and the Church.
Paul opens by giving thanks for them because he’s heard about their faith in Christ Jesus and of their love for the saints of God, but also because of what he shared in the previous verses: “…and you also were included in Christ when you heard the word of truth, the gospel of your salvation. Having believed, you were marked in him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession—to the praise of his glory” (Eph. 1:13-14).