This is driving me nuts. Back in (I believe) the 80s, in SF&F magazine, there were several short fantasy stories about a pair of women, one a warrior, the other a wizard, and they traveled their world, but were under a geas to help women in need. I think it was the sword the warrior carried that caused this, but I'm not entirely sure anymore. The author in question went on to write novels.

It's driving me nuts, because I can't remember who it was. Maybe Mercedes Lackey, but a look on her website didn't help.

Does anyone know what I'm talking about?