Get the Sack, Be Sacked

What does the idiom “Get the Sack, Be Sacked” mean?

Definition:

To be fired

For example:

“I just got the sack, and so did 20 other people. I have three hours pack up my things and leave the office.”

Notes:

“Be sacked” is known and understood on the USA, but “get the sack” is much less common.