The Power of the Echo flows through you?

Randomly after losing the lvl 25 gladiator quest I got revived and went in and got a buff "The Echo" along with the flavor text over it "The power of the Echo flows through you. You take less damage and deal more damage." as well as the chat text "The Echo grants you strength beyond your limits!"

There was no timer on it, it lasted until the mission was completed. Is there any specific cause for this or is it just something that can sometimes happen if you lose an instanced quest? Have lost a few before and never seen it.

It's a buff added if you fail a solo story quest - it was added into the game in reaction to complaints made by testers in the Beta that some of the solo story/class battles were too difficult to do on your own. It appears if you fail a solo story (instanced) battle and then immediately repeat it - if you log out and then attempt it later, the 'Echo' buff will not occur.

As for the 'Echo' itself, well, that's an important part of the storyline which is explained later in the game. ;)

Oh I know what it is, just never saw that. Thanks for the explanation :)