Have you seen the recent television ad with Abe Lincoln and his wife? She asks him if the dress she is wearing makes her look fat. Honest Abe timidly with his hands indicates “a little”, and she storms off.

Is honest Abe really being honest or is he being truthful?

Truth is, as true or actual state of a matter.
Honesty is being honourable in principles, intentions and actions. One can be truthful in what they say, but not honest in their intent.

For example:
“Do these jeans make me look fat?”
“No, the jeans don’t make you look fat!”

(The responder is telling the truth, it’s not the jeans that make the wearer look fat. But if they were being honest they would have replied, “No, the jeans don’t make you look fat – it’s just you that’s fat!”)

So good ole Honest Abe, was not being so honest, he was being truthful.