The word “mysticism” comes from a Greek word, mysterion, which means “secret ceremony”. The people who have touched the unknowable gather together to share. The sharing is not verbal; it cannot be verbal. The sharing is of their being; they pour their being into each other. They dance together, they sing together, they look into each other's eyes, or they simply sit silently together.
That's what was being done with Buddha, with Krishna, with Jesus, in different ways.
The lovers of Krishna were dancing with him. That was a mysterion, a secret ceremony. If you look from the outside at what is happening you will not be able to know what is really the case. Unless you become a participant, unless you dance with Krishna, you will not know what is being shared, because that which is being shared is invisible. It is not a commodity, it cannot be transferred from one hand to another; you will not see anything happening like that. It is not objective. It is the flowing of one being into another, flowing of the presence of the Master into the disciple.