Redemption was a price you paid to a creditor, to liberate a person or a piece of property into your own hands. Boaz, as described in the book of Ruth, paid a price to creditors to free up Elimelek's property. Boaz also obtained Ruth as his bride in the price, which was his real goal in the transaction.
This is what Christ did for us on the cross. His death was a redemption-price. He didn't make redemption merely possible, in some hypothetical way. He paid a real price when He died.
Christ also redeemed real people, not potentialities. He redeemed us -- meaning, He had specific people in mind when He died. The infinite worth of Christ's righteousness, and the authority of His throne, makes everyone forgivable in principle, but His redemption price was paid only for "us."
Liberals limit Christ's death to only a symbol of love. Though it's true that some portions of the New Testament use the cross as a motivating example of love, it was an example of redeeming love. If Christ wasn't doing something saving for us, then His merely dying wasn't love, and didn't mean anything. A man who throws himself in front of a truck to save you has acted from love. A man who throws himself in front of a truck even though you were in no danger, is insane.
To whom or to what did Christ pay the price? This verse says that Christ's redemption freed us from the curse of the Law. Since God is the giver and Guarantor of the Law, that means Christ's price was paid to the God the Father.
C.S. Lewis was wrong when he depicted Aslan dying to pay Edmund's debt to the White Witch. Freedom from Satan is one of the wonderful consequences of Christ's death for the believer, but Satan did not hold the debt. God was the creditor.
How did Christ's death achieve this freedom? Death on a tree. The moment God dictated that anyone hung dead from a tree is cursed of God (in Deuteronomy 21:23), Christ had to die that way. Christ could not have died by hanging, or lethal injection. Our problem was the curse of God's Law, so Christ had to absorb the force of that curse in our place.
This is another reason why it is highly foolish to teach that we need to keep the Law in addition to faith, to be saved. The Law's power to curse us was destroyed by Christ's redeeming death. The reason there is now no condemnation for us in Christ Jesus is because Christ absorbed the full force of God's condemnation in our place.
Will you be humble enough to receive this gift? Or are you still committed to the foolish project of earning God's approval?