Justice Must Be Served/A Gift of Silence is a quest received from The Mages' Collective Quest Board.
Background
The Collective needs a courier to effectively bribe Knight-Commander Harrith with ten Lyrium Potions, thus solidifying the relationship between the Templars and the Collective.
Walkthrough
There are two options here:
- Give the potions to Knight-Commander Harrith (located by the Windmill in Redcliffe Village), and move on. The quest seems to take the 10 least powerful Lyrium potions you have, so it would be wise to have at least 10 Lesser Lyrium Potions in your inventory, otherwise the completing the quest may cost you more silver in raw ingredients than you earn.
- Inform "The Man" about the illegal dealing (The Man, in this case, being Knight-Commander Tavish located in the Denerim Market District). He will still take the potions as evidence.
Return to any representative of the Mages' Collective for a reward.
Result
The reward is, regardless of the path chosen, 1 
It is still possible to side with Knight-Commander Tavish after completing the quest with Knight-Commander Harrith. In this case he will take 10 more lyrium potions and a "note" from you and reward you with an additional 1 .