All humans participate in Oneness, although their body and mind are in the “built-out-of-Oneness universe of duality”. This reality is like a planet, with liquidity at the center, and solidity at the edges… but this is a very limited metaphor.
We humans all have flashes of the Oneness breaking into our lives.
Poets write these flashes in poetic terms.
Scientists write them in scientific terms.
Lawyers and leaders write them in their terms, and possibly to suit their purposes.
Teachers write them in terms that they hope their students will understand.
Religious persons like Jesus, Buddha, Islamic writers, and others, past, present…. and future… have had deep impressions of the Oneness, and tried to teach what they learned.
The similarities between persons teachings in different times and different locations are due to the impressions coming from the same source, which is the Oneness.
The dissimilarities could be due to either their own lack of deeper understanding, misunderstanding of their teachings by their followers, or a purposeful change to create a tribalistic religion which excluded those who the followers didn’t want in their group. Or all of the above.
As “oneness reality” shoots its light through the hard surfaces of duality, it varies in clarity, based on the biases of those who receive it.
Mystics seem to have more “cross-system” similarities in what they believe than more “orthodox” groups. This would seem to be because the mystics are dealing with the truth at a level closer to the original Oneness substance.
The further into the dual world which one focuses on these “truths” or “realities”, the more likely they are to see a truth which is narrow, very defined, and literalistic in nature.
The further into the dual world which one focuses on these “truths” or “realities”, the less likely they are to see a truth which is broad and probabilistic in nature.