When Adam and Eve sinned, one major consequence was that the entire human race was sold into slavery to their own sinful natures and come under the direct influence of Satan.
Redemption is Jesus buying back the freedom of the human race with the price of His own blood. so that the Sin-Debt is now fully and permanently paid for.
The Bible says, "the soul that sinneth it shall die." Ezekiel 18:20 But the Bible also says, "without shedding of blood there is no forgiveness." Hebrews 9:22
So, for God to be able to forgive us, Jesus had to pay the price for the sins of the human race with the shedding of His own blood.
We were once owned by God through creation, became lost to Him through rebellion but now are re-owned by Him through redemption!
Therefore, instead of being under the dominion of Satan we are now under the dominion of God, our sin-debt is "paid in full" with the blood of Jesus.
The Bible says, "In whom we have redemption through his blood, even the forgiveness of sins,” Colossians 1:14
But God will redeem my soul from the power of the grave: for he shall receive me. Selah. Psalm 49:15