The letter to the Ephesians is written to “the saints, those being faithful in Christ Jesus” (Ephesians 1:1); importantly, it is not written to “those believing in Christ Jesus”, but “those faithful in Christ Jesus”.
We come to verse 14 and find that “you were sealed with the Holy Spirit of the promise; the One who is the downpayment of what is promised by God to His people, concerning the redemption of the purchased possession” (Ephesians 1:13-14).
The redemption therefore isn’t completed at conversion and receiving of the Holy Spirit; it is, in the Greek, the arrabon, a downpayment only, a deposit or pledge on our redemption that must be worked through in our lives.
At this point, what has happened is that the eyes of the heart have been enlightened, so as to know the hope of His calling, the riches of the glory of His inheritance in the saints and the greatness of His power towards us (Verses 18-19). For too many, however, this has become the final destination; but it is not meant to be the outcome of His calling, only the opening of the new pathway before us. This is why Paul prayed that the faithful saints at Ephesus might go on to receive the spirit of wisdom and revelation in the deeper knowledge of Him” (verse 17).
The writer to the Hebrews also made the same point;
“Wherefore, leaving aside the doctrine of the first principles of Christ, let us press on unto perfection” (Hebrews 6:1).