I've read commentators who feel that the lawyer's question suggests a sense of entitlement, as he uses the word "inherit."  Perhaps, so, but perhaps it also shows awareness that eternal life is a gift, even as one participates in doing/fulfilling/acquiring it somehow.  I do not hear this as a question about ensuring that one gets to heaven and not hell, but a question about the whole matter and purpose of life itself.  This is a "what is the meaning of life?" or "what is the chief end of man?" sort of questions.  Westminster Shorter Catechism:  What is the chief end of man?  To glorify God and enjoy God forever.