What redemption means
Redemption describes release secured by the payment of a price. In this verse the price is not money or human merit but Christ’s blood—His life given sacrificially on behalf of sinners.
Paul says that believers “have” redemption in Christ. It is a present possession grounded in what Christ accomplished, not merely a future possibility earned through good works.
The forgiveness of sins
Paul explains redemption with the phrase “the forgiveness of sins.” God does not ignore sin; He forgives on the basis of Christ’s atoning death. The plural “sins” draws attention to real acts of transgression from which forgiveness is needed.
Elsewhere Paul describes forgiveness as the cancellation of a debt and justification as a declaration of righteousness. These truths are closely related aspects of salvation in Christ.
According to the riches of his grace
God forgives according to the riches of His grace, not according to the worthiness of the recipient. Grace is God’s unmerited favour expressed abundantly in Christ.
The surrounding passage places redemption within a larger account of spiritual blessings: election, adoption, the revelation of God’s will, an inheritance, and the sealing of the Holy Spirit.