I would agree with the phrase to an extent, because it says that if there's something out there that would cause you to lie, then there's probably going to be something out there that could get you to steal, and then maybe even to kill. It's not necessarily saying that liars turn into thieves and then killers, but that if there's something out there that can tempt you to lie, maybe something else could tempt you to steal or kill.
And really.... wouldn't you think that that's true? Isn't there always something that could possess you to do that? I mean, I wouldn't like to think that I would ever steal or kill. But what if I was put in a hard situation? What if a family member's life was on the line? I'm just not sure how far anyone could be pushed if the stakes were that high.
And I think that all goes along with the message of this message:
If you'd be willing to lie for something, you'd be willing to steal for something. And if you'd be willing to steal for something, you'd be willing to kill for something.
That's just how I read it.