Samsara stems from Nirvana. Nirvana is not attained through Samsara. Samsara is an illusion which the conceptual mind continuously creates. It never departs from Nirvana, because it is not “real.” The moment you object to this concept, and begin to conceptualize, you are back at work creating Samsara. You’re never departing from Nirvana; this is impossible. It is only through Nirvana that Samsara can be created. Note how this is the opposite of the way this issue is typically approached. Samsara is effort, Nirvana is effortless. This is why Karma permeates all of Samsara. Karma is intentional action. It is an active process, and through this active process Samsara comes into existence.
Imagine that you are running. This running is an intentional effort. The moment you stop running, you are still. Stillness is the natural state. It does not take intentional effort to be still. You stop making intentional effort to run, and you are still. This is how it is with Samsara and Nirvana, illusion and reality. I say “illusion,” but I do not mean this in a derogatory sense. Nirvana expresses itself through the infinite manifestations of Samsara.
Many Spiritual types place great emphasis on shedding illusion, finding the “truth,” which naturally opposes what is “false.” This discrimination is of the same conceptual mind that brings about the “illusion” in the first place! They are missing their own truth, by being so caught up in separating themselves from “illusion.” You see, Nirvana expresses as Samsara. Samsara is inherent in Nirvana. So when you really grasp the “truth,” you see the non-dual, and all discrimination ends. This opens up true freedom, which is why enlightenment is called liberation. Now everything is just a big play, or experiment. When you see “All as One,” as the common expression goes, you are free to participate in any aspect of reality you would like. You don’t become attached to any particular aspect either, because that doesn’t make sense either, in light of this Truth which has no opposite. Now you can float through eternity, playing with the infinite amount of potential causes and effects.