Yesterday several people in a workshop introduced themselves as honest or candid. As the workshop progressed, however, I realized a flaw in their use of honesty. They seemed to say whatever was on the top of their minds at any given moment, regardless of whether their comment was applicable and with no thought as to how their tone affects their meaning.
Something should be said now if it passes all three of these tests:
1) it is true (honest) to the best of your knowledge
2) it is useful
3) the person(s) who needs to hear it can hear it from you.
Yes, always speak the truth. Frankly, it is a lot easier than trying to remember to whom you made up what. But decide before you speak: is what I'm saying necessary and useful? Yes? Then you must say it; otherwise, you will have committed the sin of omission. This is a form of lying.
Now that you know you must say it, you must decide who needs the information. Then, will that person hear the information from you, or must it come from some other source?
Finally, assuming you are the right person to say it, think about how it will be received. Be sure your truth is told with mercy.
It will not be heard otherwise.