In spirituality, Nondualism, also called non-duality, means "not two" or "one undivided without a second". Nondualism primarily refers to a developed and mature state of consciousness, in which the dichotomy of I-other is "transcended", and pure awareness is the result and can be described as unified and "without dichotomies".  In the Guardian context, nondualism can be considered the stages of integrated spiritual ascension that occurs when fully committed to expressing higher truth and Personal Integrity, which is a natural byproduct of the embodiment principle contained in the first practice of the Law of One, Unity consciousness.
Essentially, the state of nondualism also reflects spiritual integration within the Lightbody layers that results in the perfect alignment with gaining dominion over one's consciousness, having synthesized the inner and outer polarities of the mental, emotional and spiritual layers into oneness. In the state of inner unification, we become fully centered in the authentic core self, which aligns us to our highest expression and inner spiritual essence which are the male-female energies uniting into Sacred marriage or hierogamic union. When we are in Energetic Balance and in harmony with our inner aspects, our inner male and female principles are synthesized and united. Thus, we align to the harmonious interaction within the natural laws of creation, and perfect will, which reflects the higher will of God or the divine will of creation.
When the individual has achieved a state of unity or Nondualism, their thoughtforms, feelings and actions are coherent and aligned with the core essence of their inner spiritual being which fills their consciousness with light. We could also compare this state to achieving Personal Integrity and representing this energetic integrity in the inner and outer worlds, living as your core authentic self. In unity, the mental body, emotional body and action principle are synthesized into one. As you think, so you feel, and so you will act, as one within, this is the principle of nondualism brought into physical embodiment.
Unity Consciousness is the first practice of the Law of One, in the belief or direct Gnosis that every being is an individualized expression of God, which our ultimate spiritual purpose is to give expression to God in order to embody our Heroic Probability, the highest fulfillment of our Krystic divine eternal nature. When we experience or feel into the truth of unity consciousness, our connection expands with all of life. Then we feel spiritually inspired to dedicate our life to the seeking of truth and to live in dedication to serve truth principles.