Sage Sankara said: ~ Liberation will never come without realizing the Oneness.+

Oneness means Advaita. Identifying the Soul hidden by the universe as it is through Advaitic wisdom the oneness arises.

 Swami Vivekananda: ~ Oneness (Advaita) is the Secret of Everything.

Lord Krishna: People did not care for Advaita; they wanted religion; hence Advaitic wisdom got lost. That is why Lord Krishna calls it "the supreme secret.

Sage Sankara said: ~ Liberation will never come without realizing the Oneness.

Oneness is the nature of the Soul, the Self. Oneness means Advaita or nonduality. When the universe appears the duality appears. When there is duality then there is no Oneness. When there is Oneness there is no duality.

Advaitic wisdom dawns on its own in the mids of the dualistic illusion when you realize the consciousness oneness of form, time, and space.

By saying I and you are one the Oneness will not arise.

There is no Oneness in the realm of ignorance.

There is no Oneness when ‘I’ is present.

There is no Oneness when the mind is present.

There is no Oneness when the dualistic illusion is present.

There is no Oneness when the universe is present.

There is no Oneness when the waking or dream is present.

There is no Oneness when the individual experience of birth, life, death, and the world is present.

There is consciousness Oneness in the midst of the dualistic illusion when Advaitic wisdom dawns. :~Santthosh Kumaar