Triangle strainer test.
A person came to Socrates and said to him with great enthusiasm: Do you know what you recently heard about one of your students?!
Socrates replied: Before you speak, I want to conduct a simple test on you, which is the “triangle filter” test.
?The man asked him in amazement: What is this strange test
Socrates answered: It is a test that we must conduct before we speak. We will begin to filter what you are going to say.
?The first filter is called the truth. Are you sure that what you are going to tell me is the truth
The man said, “No, I’m not sure. I heard it from….”
Well, Socrates said, then you're not sure whether it's true or not. Let us move to the second filter, which is the filter of goodness. Is what you are going to say to me for good?
He replied: No, on the contrary.
Socrates continued, “Okay, do you want to tell me bad news, even if you are not sure of its authenticity?” However, we will try the last filter, which is the benefit filter. Will what you say to me bring benefit to me?
The man answered in shame, “No, it is of no use.”
Socrates concluded the conversation by saying: If what you want to say I am not sure of its truth, nor is it for the good, nor is it of any benefit, then why do you want me to listen..!
Source: websites