"Father forgive them, for they know not what they do"
These words of Jesus on the Cross is the ultimate word in Forgiveness. Forgiveness for those intent on crucifying him.
Mathew 18:18 " I tell you the truth, whatever you bind on earth will be bound in in heaven, and whatever you loose on earth will be loosed in heaven".
The reference here on binding is to the wrongdoings (sins) and (loose)forgiveness. If you do not forgive others their wrong doings and hold these as sins, then their sins will be retained. This makes it imperative that though you have led a good life, you will have to return to clear the wrong done by others because you held it against them, therefore you have to return in order to forgive them and clear their sins. This causes one to be born again to clear all blemishes before return to the Father. This was known to Jesus, who did not want to get into the cycle of rebirth . That is why he said
"Father forgive them, for they know not what they do"
This emphasizes the importance of Forgiveness in our lives.