How does this text explain the all-pervading principle of the universe and why people might fail to recognize it?

The source explains that a single, undifferentiated principle pervades all of existence, from the creator Brahma down to the smallest blade of grass, including all moving and non-moving things. This principle is constant, being the same here as in the hereafter. According to Chapter 37, this reality is devoid of worldly qualities. However, when it is combined with adjuncts (upadhis), a soul that is deluded by ignorance can be misled and fail to perceive it as the true Brahman, thus seeing it as something else.