An old Sufi tradition advises us to speak only after our words have managed to pass through four gates.
At the first gate, we ask ourselves, "Are these words true?"
If so, we let them pass on; if not, back they go.
At the second gate we ask; "Are they necessary?"
If so, we let them pass on; if not, back they go.
At the third gate we ask; "Are they beneficial?"
If so, we let them pass on; if not, back they go.
At the fourth gate, we ask, "Are they kind?"
If so, we let them pass on; if not, back they go.
If the answer to any of these is no, then what you are about to say should be left unsaid.