The Thorn Birds appears to be that the wages of sin is death.Those who engage in sinful activities lose someone dear to them. Fiona had a child before she was married to Paddy Cleary; that child, Frank, eventually winds up in prison for thirty years.Meggie loses both de Bricassart and Dane. De Bricassart loses the son he never knew and eventually his life. God, as envisioned by Colleen McCullough, is not only a jealous God; he is a vengeful one, as well.