I believe the founders of all the religions such as Jesus, Buddha etc. would have perceived the real truth in an altered state of consciousness. But however, as these religions stand today, I guess they have severely distorted the messages from these people. Besides, its extremely difficult to explain these things in our languages.
Even I have a really tough time, explaining some complex existential concepts to people. It took me a lot of work over many years to really be comfortable with questioning certain beliefs even. I am misunderstood MOST of the time. I cant even imagine how difficult it would be for an enlightened person to pass on the knowledge.
Its best to trust your direct experiences the most.