Thanks, everyone, for your thoughts!
4evermom, you may very well be right -- he might just be trying on the phrase, seeing how it fits, seeing how we respond. It totally astounds me every day the phrases that he picks up sometimes!
Mothra, we pretty much did what you suggested -- tried not to make a big deal out of it, but explained to him that I didn't hit him. I told him even though I was angry and he heard that, I would never hit him or hurt him because I was angry. I'm trying hard not to overtalk things with him, but it's really difficult sometimes!
pickle it, I'm glad it was a short-lived phase for your daughter. Did you ever get the feeling that she was worried that you would hit her? I think that's one of the things that I'm afraid of. Lately Nate seems to be processing a lot of fears by telling us things have happened to him that he's afraid of (most recently, that he's been bitten by a spider, after he got scared by a spider on my DH's shirt). I want to make sure that he isn't afraid that I'm going to hit him.
Piglet, if my DH did that it'd drive me batty. I definitely agree about not treating it as "lying;" I know he doesn't have any concept of that at his age. I just want to make sure that if there's something serious underlying this (maybe, like I said above, a fear of being hit) that we address it. We are the only non-spankers in our extended families, and I am adamant that he not see any spanking, but at the same time I'm afraid he might be exposed to it and I want to make really, really sure that it's very solid in his mind that his Mama and Daddy are never going to hit him, and aren't going to allow anyone else to do it either.
Okay, that's been a bit wordy, but I really wanted to say thanks to you all for your stories, letting me know I'm not alone, and advice. I really appreciate it. I don't say much in this forum, because so far this parenting ride has been easy for us, but I sure do learn a lot here.