The small part of body can makes the biggest corruption. The corruption of tongue can't be amended . If you say something that hurt your best friend, especially when say something in front of others to your friend. You are not able to taken the word back. Your regret can't amend the relation between you and your friend.
I don't know why people don't control their tongue , when they are among their friend , or relatives they make a joke and offend others. Sometime we heard about something and narrate it to other while we are not sure what we heard is truth.
Look at the following story.
There was a good man(scholar) who was reputed to hold knowledge in high esteem. One day an acquaintance met the great scholar and said, "Do you know what I just heard about your friend?"
"Hold on a minute," the scholar replied. "Before telling me anything I'd like you to pass a little test. It's called the Triple Filter Test."
"That's right," the scholar continued. "Before you talk to me about my friend it might be a good idea to take a moment and filter what you're going to say. That's why I call it the triple filter test. The first filter is Truth. Have you made absolutely sure that what you are about to tell me is true?"
"No," the man said, "actually I just heard about it and..."
"All right," said the scholar. "So you don't really know if it's true or not. Now let's try the second filter, the filter of Goodness. Is what you are about to tell me about my friend something good?"
"No, on the contrary..."
"So," the scholar continued, "you want to tell me something bad about him, but you're not certain it's true. You may still pass the test though, because there's one filter left: the filter of Usefulness. Is what you want to tell me about my friend going to be useful to me?"
"No, not really..."