Proveb: People who live in glasshouses shouldn't throw stone

[Jupiter]

Hi teachers,

I know when we throw stone on glass, the glass will break.
But what does the above proveb exactly imply/mean?

Thanks in advance

Jupiter

[Pamela]

Hi Jupiter,
The proverb means that you shouldn't insult, hurt, reprimand, criticize other people as they can do the same thing in return.

A.Look at what time it is... you are late again!"
B. "Hey, how often are you not on time? People who live in glass houses should not throw stones."

[Haihao]

Just some variations (not strictly synonymic though):

The pot calling the kettle black.
It takes one to know one.
It takes a thief to catch a thief.

Even more unstrictly:

Six of one and half a dozen of the other.
It's as broad as its long.

Haihao

[Saturn]

Another variation i like:

Don't carry a gun if you're not willing to get shot.