It means the same as for Christ's sake! but please note the spelling & syntax.
{John}: Hey Josh, quick! Check out that blimp about to crash into a radio tower!
{Josh}: For Christ sakes John, that looks just like the pictures of the Hindenburg crash that I've seen!!!
by Telephony September 25, 2013
Interjection of annoyance or anger, like dammit!, son-of-a-bitch!, etc.: much stronger than "for Pete's sake!"
Stop playing with those girlish toys and act
like a boy, for Christ's sake!

also "crissakes!" or "Christ sake!"
by Jon64Bailey January 6, 2009