It's from the episode "Sacrifice: Part One"
Xena: You're a god. It won't kill ya.
Callisto: No-- won't kill me. But it will keep me locked up long enough for you to get to my precious little baby. Oh, well--back to basics. Ouch! Don't do that. The best you can hope for is a stand-off-- and who do you really think is going to tire out first-- huh? Well, I gotta give you credit for trying. You should have kept running. I couldn't use my powers in there, but out here-- well-- can you say, Nighty-night? [Screams] [Gasps] No!