There are many ways to execute a person. Crucifixion is probably the cruelest method. The punishment was reserved for criminals.
This was the price for the sins of humanity—from the creation of the world to the last person who will walk the earth. Our debt has been paid. Although a painful event to remember, the death of Our Lord brought us freedom. We need not live in fear of punishment because we have been acquitted. We are guilty as charged, but we have been forgiven. Jesus paid the price.
The only explanation is love. From beginning to end, the Passion is about the love of God for us. We unite our sacrifices, our pain, our suffering to the Passion on the Cross. “We adore you oh Christ and we praise you. Because by Your Holy Cross You have redeemed the world.”