set in stone 

Colloquial description of an item (document, schedule, contract, etc.) that cannot be altered without great effort (and possibly some destructiveness) for one reason or another.

Probably derived from how the ten commandments (Exodus 22:* in your bible) were produced on stone tablets, as it requires effort to modify a document that is etched into stone.

See also set in jello for a good opposite.

Once you sign the contract, the terms are set in stone.

set in stone by Dennis The Tiger April 6, 2005

Set in stone 

(pertaining to holidays) A promise that absolutely will not be broken, unless it was only made verbally by management, in which case it turns out the fuckers are guaranteed to change it.

You know those holiday dates? You can take them as set in stone.

... about those holidays you booked... you're going to have to come in those days, I don't give a shit what you think.

Set in stone by ochrann January 10, 2020

Set In Stoners 

A married or dedicated couple who collectively enjoy marijuana and its effects.

Ryan and Dakota, the Set in Stoners of the neighborhood, celebrate their anniversary every year with a couple of joints.

Set In Stoners by GoldenGirlsDRM August 15, 2020