Time, like space, is a core aspect of the separation and a major teaching device of the ego. It appears to affect both the world and all its contents, including bodies. We are born, age, get sick, are injured, and eventually die. All this takes time. Yet A Course in Miracles emphasizes that this understanding of time is an illusion, and that the only actual time is now, which it refers to as the Holy Instant. In timelessness, there are no distinctions or differences or intervals at all, which undoes judgment and leaves us effectively at peace. Timelessness is kin to Heaven, a state of remembered oneness, in which all Creation is eternally joined in a single shared experience. Time is a most persistent illusion, even more than matter, and represents a major learning challenge for many ACIM students.