(idiomatic, sarcastic) Used to indicate that one is glad, or at least unmoved, to see the addressed person leaving.

Alternative form of let him who is without sin cast the first stone

Only those who are faultless have the right to pass judgment upon others (implying that no one is faultless and that, therefore, no one has such a right to pass judgment).

Alternative form of let him who is without sin cast the first stone

A command that another person leave, thereby impliedly having the door hit them on the buttocks as they pass through it.

Seek to dispel ill-will before a day’s end, and not to act upon desires for vengeance.