A glass house is brittle and may casily crash down if stones are thrown at it. And a person who himself lives in a glass house should not throw stones at other’s, because it may provoke others to damage his own house too.
In the figurative sense the proverb means we should not abuse others as we may get the same by turn. Yet we are often involved in such a wrong way because finding fault with others is a common human weakness. It is one of the most popular pastimes to sit done in idle groups to chat at the shortcomings of others.
But while doing so, we hardly realise that we expose ourselves too to criticism and condemnation of others. None of us is born perfect, and faults can be found in each of us in different degrees.
So, we should avoid finding fault with others. Paying in the same coin is the rule of our society. Here respect wins respect and hatred breeds hatred. Only prophets have the right to find faults of human life since they do it from love, not from any ill-motive or malice.
So far as common people are concerned, it is best to forgive and forget. We should do unto others what we wish to be done by others.