This episode was a favorite of mine. Besides featuring some background on Stewart and featuring some awesome Flash moments, this was the first time in The Justice League series we hear the Oath and in an awesome manner. The Manhunters (The robot security force that predates the Green Lanterns, and was eventually discontinued after a violent massacre.) were seeking revenge against the Guardians and the Corps as a whole. They nearly succeeded when the leader of the Manhunters absorbed the power of the Battery. Not wanting to take it lying down (and to get back at the individual who set him up) Jon stepped up and recited the oath and you can see the result above.  It was this moment I became a Green Lantern fan.