John 16:15: EMA ESTIN -- why accusative?

Jonathan Robie (74144.2360@compuserve.com)
21 Aug 96 09:48:47 EDT

This may be a very basic question, but why is the accusative used
in the phrase "EMA ESTIN" to say "is mine" in the phrase "all that
the father has is mine"? The complete verse is:

PANTA hOSA EXEI hO PATHR EMA ESTIN; DIA TOUTO EIPON hOTI EK TOU EMOU LAMBANEI
KAI ANAGGELEI hUMIN.

I don't think of the accusative as indicating possession, I thought
that's what we pay the genitive to do.

Thanks!

Jonathan