“New Ground” is episode nineteen of season three of Stargate SG-1.
SGC activate a just-excavated stargate, which was dialled using a programme that regularly tries stargate addresses that previously hadn’t worked. Otherwise, that would be a rather incredible coincidence. At least they came up with a decent explanation for that.
SG-1 go through the stargate, as the people on the other side seem to be at a comparable level of technology. They actually are somewhat superior.
The team winds up a decades old war, in which the stargate is a rather integral part of the argument that started the war. And some of the people on whose continent they landed are not happy, because that proves their side of the argument wrong, and refuse to believe it (because it’s a religion). Everyone but Teal’c is captured.
An example of closed-mindedness at work, where anything that doesn’t agree with your beliefs is a trick.