be carved in stone(redirected from be set in stone)
be carved in stone
To be made permanent, typically of a plan or idea. We might get brunch next weekend, but nothing is carved in stone yet.
be carved (or set or written) in stonebe fixed and unchangeable.
The reference here is to the biblical Ten Commandments, written on tablets of stone by God and handed down to Moses on Mount Sinai (Genesis 31:18).