An experience that can only be accomplished by the individual, and then, only by the individual alone. For example, if I explain love by saying that my heart was racing, my palms grew sweaty, I had butterflies in my stomach, and I did not know what to say, those people who had experienced this would immediately sympathize with what I was trying to say. On the other hand, those who had not had this experience, might justifiably conclude that I was merely having some kind of anxiety attack. Only your personal experience would allow you to sympathize with what I was trying to express. Furthermore, although that description might be enough for you to know what sensation I was referring to, it is not the sensation, and thus totally inadequate insofar as explaining what love actually is.
Love transcends words.
That's the whole problem in a nutshell. All religions are stuck using words to try to express an experience, that by it's very nature, transcends words themselves. The experience they seek to explain, ultimately cannot be explained, only experienced. This is the reason that religions usually attempt to teach their lessons through the use of parable, analogy and metaphor. When a religion gets bogged down in the words of the lessons, it cannot help but lose the spirit of the experience.