Get the sack
Be dismissed from a job.
The probable derivation of this phrase is an allusion to tradesmen, who owned their own tools and took them with them in a bag or sack when they were dismissed from employment.
It has been known in France since the 17th century, as 'On luy a donné son sac'. The first recorded English version is in Charles Westmacott's The English Spy, 1825:
"You munna split on me, or I shall get the zack for telling on ye."
In his 1869 'Slang Dictionary', John Hotten records these alternatives - 'get the bag' (from the North of England) and 'get the empty' (from London).
See also, the order of the boot.