In the Christian Bible the parable told about the prodigal son tells of a young man who goes forth into the world and does not follow his father's guidance. Yet, when his son returns home he is received by the father with open arms and love.
The parable is used to represent the relationship between mankind as the son (each individual) and God as the father. Man is going to commit many sins in his life and will not always go forth and follow the "word" of his father. However, God will always open his arms to receive man, the child who is in essence the prodigal son, with forgiveness for man's actions or sins.
Yet, if man can be so willingly forgiven by the father, then man must also be able to offer such divine forgiveness of one another.