“The First Commandment” is episode six of season one of Stargate SG-1.
When SG-9 fails to return from a world with extremely high levels of UV radiation after sending a signal through the stargate, Colonel O’Neill’s team gets sent to investigate.
It turns out the commander of SG-9, Captain Jonas Hanson, has gone barking mad. The natives thought he was a god when he originally appeared – a not uncommon happening for the SG teams, as they come through the same ring that their gods do – and he didn’t deny it. Now he actually believes it himself. Captain Hanson is also Captain Carter’s former fiancée.
SG-1 has to expose him as the fraud he is – even if it’s a con he now believes himself.