Adam Clarke on Luke 12:13

Speak to my brother, that he divide - Among the Jews, the children had the inheritance of their fathers divided among them; the eldest had a double portion, but all the rest had equal parts. It is likely the person complained of in the text was the elder brother; and he wished to keep the whole to himself - a case which is far from being uncommon. The spirit of covetousness cancels all bonds and obligations, makes wrong right, and cares nothing for father or brother.