Season 9: Sins of the Horadrim will have you progressing through its Seasonal Questline, which requires that you reach certain tiers with your Horadric Knowledge now and then.
This will come in the form of a Repeatable Quest that will take place until you have reached the required tier to unlock the other Seasonal Quests.
The Truths That Lie Within serves as a guide to help you collect a certain amount of Horadric Knowledge so that you can proceed with the Seasonal Questline.
How To Get The Truths That Lie Within Seasonal Quest?
This Seasonal Repeatable Quest becomes active once you have no other quests and have the option to grind for more Horadric Knowledge.
In between certain Seasonal Quests, you will need to follow this Repeatable Quest as a guide until the next quest has been unlocked.
If you are done with the Seasonal Questline of Sins of the Horadrim, this Repeatable Quest will serve as a guide that remains active until the last Horadric Knowledge tier is reached.
The Truths That Lie Within Quest Walkthrough
While this quest is active, you will need to complete Nightmare Dungeons until you have gained enough Horadric Knowledge to progress to the next Seasonal Quest.
This requires that you activate a Nightmare Dungeon using a Nightmare Sigil and complete it, as well as its Horadric Strongroom, until enough Horadric Knowledge is obtained.
Nightmare Sigils can be activated to turn a random dungeon into a Nightmare Dungeon, and you can teleport to it by selecting it on your map.
Once you have reached the next tier that unlocks another Seasonal Quest, this Repeatable Quest will deactivate until you need to unlock another quest or grind for the last tier.
The Truths That Lie Within Quest Rewards
The Truths That Lie Within quest does not provide any rewards but simply allows you to track the amount of Horadric Knowledge that you need.
Completing this quest may be done multiple times, as it serves as a way to close the gap between your activities as you progress through the season.
Verdict
To make things simple, The Truths That Lie Within does not provide much other than a way to keep yourself reminded that you need to progress with your Horadric Knowledge.
This beats repeatedly heading back to Cerrigar to check the Horadric Focus for how much Horadric Knowledge you currently have and need.
The best way to quickly progress with this Repeatable Quest is to make sure you upgrade your build along the way and complete the Nightmare Dungeons and Horadric Strongrooms quickly.
