The Knowing is not touched by anything at all. Greed, lust, hatred, jealousy, disgust; non of this can touch the Knowing. The Knowing can know itself, but even this doesn't touch it and it knows this too. It is a bit like a camera that can't photograph itself, yet knows of it's own existence in the sense that when it malfunctions it's photos are correspondingly affected.
Similarly, when the Knowing is affected by delusion it's view of the world is correspondingly affected. But as soon as it knows this this knowing arises and is completely untouched by it: in this sense it can be said to be always fresh.
Anything coming from delusion is knowable in a detached way, it can be investigated and described, but the Knowing can only be known. The practitioner may talk about this, but as soon as he does so the knowing seems to disappear, becomes obscured, only to return to view as soon as the dissertation stops and a resumption of the knowing is effected.
All else can be said to be a mirage, it only exists while it is not scrutinised: the knowing however, holds steady, unchanging and untouchable whilst under the closest scrutiny, but nothing can be done to it, with it nor be said about it.