At the cross, Jesus paid the penalty of our sin He did not owe, and He paid our sins that we could never pay. A payment by the shedding of His blood at the cross to wash our sins away. Indeed, Jesus is the Lamb of God, the perfect sacrifice to reconcile us sinners to a holy God by the shedding of His blood, for without the shedding of blood, there is no forgiveness of sins.
At the cross, with nail pierced hands between heaven and earth, Jesus intercede to the Father. It was a prayer out of pure love, being concerned for those who are responsible for crucifying him and interceding to forgive them for their souls are in danger of eternal suffering in hell.
Our Lord Jesus gave His life by dying on a cross, once and for all to save us sinners, and prayed to his Father, with genuine love and mercy flowing from His heart saying -- "Father, forgive them." Jesus' prayer on the cross tells us that He made a way and the only way through His sacrifice for God to forgive us and be reconciled to Him.