Having meditated on gentleness and compassion, I have forgotten the difference between myself and others.“ — Milarepa
When we speak of non-duality what others views call oneness we talk about the highest state of selfless. When we understand love compassion gain wisdom by letting go of our ego grasping we realise the state of one the same.
The difficulty for us ordinary people is that we see subject and object, me you, this that and we got lost on everyday experience thinking that is real. Because as the Buddha Shakyamuni teach in the golden light sutra five senses five thieves in empty village.
Sutra of Golden Light PART 6 OF 21
Emptiness
Then at that time the Tathagata spoke these verses:
In numerous other inconceivable sutras, I have expounded empty phenomena in detail. Hence, here in this supreme sutra empty phenomena I will just briefly explain.
As beings of slight intelligence, ignorant, are incapable of knowing all things, hence, here in this supreme sublime sutra empty phenomena are explained only in brief.
So that all beings may certainly know, so they may be delivered from cyclic existence, through compassionate ways, methods and other means, I have expounded this supreme sublime sutra.
The body is like an empty village or house; senses are like soldiers and thieves. Although they live in the same village, they are unaware of each other.