Just to warn you, I'm probably going to use the word "threefold" a bit gratuitously. It's been a lot of struggle, but I've settled on belief in the threefold salvation. That is to say, salvation requires three things (okay, evangelicals, have your cringe and keep reading). First up, we have Knowledge (Rom. 10:14), followed by Belief (not Faith, there is a difference), which is then followed by Works (I know, I know, but I've read James through over and over and I just don't see any way out of that one). All of these together are Faith and they make a New Man. Knowledge represents the skin, the boundaries of this New Man; Belief is all the internal stuff, the substance; and then Works represents all of those oh-so-needful bodily fluids. Voila! Faith body. (Without bodily fluids, you're dead; faith without works, also dead. Dead faith getting you into Heaven? After all that talk of new life and being dead in sin, I just don't see it.)
Here's the Sunday School illustration: Knowing says "A chair is something you sit in." Belief says "There is a chair in the corner." Works doesn't say anything and goes to sit in the chair. If you're sitting in the chair, you have Faith.
Something else occurred to me through this. The vogue of late has been a return to the personal God, the God we have a relationship with. Which is not a doctrine so much as an emphasis. We've always believed God was personal, intelligent, emotive, but the Generation Y mindset isn't looking for a King, we're much more interested in a brother. So, what if interpersonal relationships can give us a much clearer picture of the Trinity?
When you are getting to know someone, you work in three spheres: knowledge, action and communication. Knowledge, on the basic level is stuff like name, age, physical description; eventually it becomes the ability to predict responses. Action is the context in which you get to know each other, what you do together as well as encompassing behavior on both sides; especially the unique behaviors you have in each other's company. Communication is what you say verbally, how you say it, as well as body language and all those other things we learned about in 'Hitch' (which I only just now realized was a pun on the marriage thing).
These things are all quite distinct in their functions, but just try to separate them when you're hanging out with friends or meeting someone new. Basic knowledge is easy to come by just by seeing someone, but their clothes and even their posture communicate at varying levels of subtlety. The way they shake your hand is a behavior that communicates what will become knowledge. If you're watching a movie and your friend bursts out laughing at the screen, you've just learned about how expressive they are, not to mention how much they liked that joke, plus all of this in relation to yourself, and a picture of their preferences just became a little clearer.
So, while the elements of relationship are very distinct and easy to define, in practical experience, they are extremely difficult to separate. You almost can't ever get only one at a time and they almost always hit you all at once. Now, if Knowledge represents God the Father, Action is a picture of Jesus, and Communication symbolizes the Holy Spirit, then that whole three-is-one thing becomes just a bit easier to grasp. At least, I think it does.