A false witness will perish,
but the word of a man who hears will endure.
Yet another unexpected contrast. We would think the second clause to say something like, "but the word of a man who tells the truth will endure." This contrast draws out the heart condition of the false witness. Such a person lies because he is not interested in a fair hearing of a case, but in getting his own way. Some lie to take advantage of another; some lie to avoid being taken advantage of. In either case, the false witness is more concerned in getting the outcome he desires than for the truth to be known.
This proverb also notes what is in the heart of the truth teller. He is interested in the truth. That is why he first takes the time to listen well before speaking. Some people pride themselves in truth-telling when they are no such thing. To speak before one has listened is to betray that one's real motive is merely to draw attention to oneself. It certainly shows a disregard for truth, because truth may come from any source, and it is the wise person who is able to listen well and discern the truth that is spoken.
Will you speak the truth today? The better question is, "Will you listen carefully for the truth?"