Commentaries:
"Redemption" implies the payment of a ransom. We have been redeemed or bought back.
"Through His blood" reminds us that making the New Covenant cost Him His life (I Corinthians 11:25).
Forgiveness here suggests "to be loosened from bondage." The Greek word-picture is of somebody who is tied up by cords or ropes. Have we, as Christians, been loosened from a political entity, as the Israelites were redeemed from Egypt? No. Were we in bondage to another human being? No. Have we been freed from sin? Yes, that is what held us in bondage. The word translated "sins" is paráptoma, which indicates deviations from the right path. We have been held in bondage by our deviations from the right path, but now we have been loosed or freed from that bondage according to His grace.
John W. Ritenbaugh
The Awesome Cost of Salvation