"When you look long into an abyss, the abyss looks into you." ~Friedrich Nietzsche
Here is the second quote. Abyss means a bottomless depth of something, it could be a bottomless pit or bottomless sea of some unsightly thing. What this quote is trying to convey is that when a person looks into this bottomless pit, depending on whether the person is evil or good--the abyss reflects what your deepest secrets are. It can reflect light or darkness, victory or downfall. It all depends on your karma and morals. This abyss can devour you, destroy you, and even manipulate you if you let it. You can never escape from your true self.
Either your true beauty or true darkness will be reflected right back at you by this abyss.