All the higher spirituality in every religion recognizes this. This is not exclusive to vedanta. Immediately reminded of iode, the new testament. Jesus says that you cannot worship god and mammon together. Either you will have one or reject the other. Where darknesses there can't be light.
Swami Sarvapriyananda teaches the Katha Upanishad, which is one of the most popular Upanishads. The scripture concerns the story of a young man who goes to the house of death to find out what happens after death. The reply describes the nature of reality and the meaning of life.