This sounds like a Stargate episode. A planet with only very old religious fundamentalists. They accept their eternity in hell but see it as a worthy sacrifice

This sounds like a Stargate episode. A planet with only very old religious fundamentalists. They accept their eternity in hell but see it as a worthy sacrifice since all aborted souls go to heaven and when their species ceases to exist they know all sin will be gone. The arrival of SG-1 threatens their plan, so they try to wage war against humans in the whole galaxy.