Redemption in the Bible has to do with how debtor’s prisons operated.
If you owed money which you could not pay you could be hauled into court and sent to debtor’s prison until the debt was paid.
***Make friends quickly with your accuser, while you are going with him to court, lest your accuser hand you over to the judge, and the judge to the guard, and you be put in prison; truly, I say to you, you will never get out till you have paid the last penny. *(Matthew 5:25-26)
To add to the humiliation of not being able to pay your debt you were not permitted to pay it yourself. Someone else had to come to the prison with the money and pay the debt for you. Even then you were not released immediately but the person paying the debt only purchased the right to take you out of prison. Purchasing the right to take you out of prison was called redemption. The person paying the debt was the redeemer. Many slaves and servants were purchased this way.
*You are not your own; you were bought with a price. So glorify God in your body. (1 Corinthians 6:19-20)
You were bought with a price; do not become slaves of men. (1 Corinthians 7:23)*
Only when you crossed the threshold of the prison door into daylight were you a slave or a servant of the person who redeemed you. At any time prior you could go back to your cell and wait for a better deal or hope that a family member comes up with the money.
Paul uses the idea of debtor’s prisons and redemption frequently. Jesus is the redeemer. Jesus purchased us from the prison of sin with the infinite price of his Precious Blood. He paid the debt. We used to be slaves to sin but now we are redeemed and slaves of Christ.
*But we had hoped that he was the one to redeem Israel. Yes, and besides all this, it is now the third day since this happened. (Luke 24:21)
Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred which redeems them from the transgressions under the first covenant. (Hebrews 9:15)
It is these who have not defiled themselves with women, for they are chaste; it is these who follow the Lamb wherever he goes; these have been redeemed from mankind as first fruits for God and the Lamb, (Revelation 14:4)*