It makes sense that the first word of Jesus from the cross is a word of forgiveness. That's the point of the cross, after all. Jesus is dying so that we might be forgiven for our sins, so that we might be reconciled to God for eternity. In the mercy of God, we receive His forgiveness even when we do what we know to be wrong. God chooses to wipe away our sins, not because we have some convenient excuse, and not because we have tried to make up for them, but because He is a God of amazing grace, with mercies that are new every morning.
As we read the words, "Father, forgive them," may we understand that we too are forgiven through Christ. Because Christ died on the cross for us, we are cleansed and united with God the Father as His beloved children.