"Free n' Clear! You're about swear an oath of ancient and great importance! After you've sworn it you will be expected to abide by it for as long as you walk in the land of the living! Speak only the truth when answering. Failure to abide by it may have grave consequences for you. Do you understand? If so say yes now."
"Yes." Said the filly meekly. Upon saying those words Celestia's horn glowed brighter and a second arcane circle appeared floating about a foot above the one on the floor.