When discussing sacraments with 6th graders, I always emphasize that the physical part of a sacrament is more than a symbol. And by the time we even get to a sacrament (Baptism), they are already familiar with God's grace and power moving through physical media such as Moses' staff, Elijah's cloak, Elisha's bones, and Jesus' tassel. Later on when we get to Acts, they can figure out on their own how handkerchiefs and shadows can transmit healing to the afflicted. Catechism class is alive with God flowing through his Creation.
Ah yes, Creation- the stuff that God made in six days and all of it was good. As I say in class, "It was all good, morally good, even dead stuff like rocks. God makes only good things, that's just his nature." But then Adam sinned, messed up not just himself but all of Creation, and the rest is history. Now we struggle against the consequences of sin, not just spiritually, but physically: we get hungry, sick, injured, we hurt, we age, we die. Now you'll recall that if we graph the 6 days of creation, as days pass, the things created tend to be more and more like God. And at the top of the graph is Adam- well, no, Eve is at the top- well, no, something higher still...sorry for digressing. Anyway, before the Fall, everything was good. But in the case of a rock, only as good a rock can be. A plant would have more goodness in than a rock; a bug more goodness than a plant, etc. More like God = more goodness. By no small coincidence that also means: more like Adam = more goodness. But the downside is that because Adam's sin cursed the Earth (and by implication the rest of Creation) the things closest to Adam took the biggest fall from grace. Let's say Adam fell 50%. And the things farthest from Adam, such as inanimate rocks and water, lost the least of their goodness- maybe 5%. So when God works miraculously through sticks, water, oil, shadows and rags, I see it as a reproach: God chooses those things on the low-end of Creation because they may retain nearly all of their original grace-goodness conductivity. Stuff near the top is more flawed, more unstable.
Now here's another consequence of the Fall: we need faith because we can't perceive all kinds of stuff that affects our existence here and elsewhere. Think about folks in Eden: did they need faith? Sin hadn't yet pried Creation into parts, so I doubt it. Or those in Heaven? No. But now, yeah, sin truncates our perception. We see only dimly, or not at all. And stuff I think I see clearly, like a tree or my wife- I bet they look way different, more tree, more wife, to a saint peering down from heaven. Sin makes it harder for us to see the Good that's woven into the fabric of the Universe. Sin's effects make us divide reality into what's "visible and invisible"; but it's actually one big continuity. Just because we see it partially doesn't mean we can't try to understand it as a single unified entity.
But how nice of Jesus to institute sacraments to bridge that gap. You know what a sacrament is, right? "A Sacrament is an outward sign instituted by Christ to give grace." That's a good Western definition. It points to the part we can see. Sacramentum is a practical word the Latin Church uses in place of the Greek word mysterion, μυστήριον. It makes perfect sense especially if you consider sacra-mentum is fundamentally a tool or means of making something holy, set apart. Like instru-mentum, a tool to construct something.
Too bad the Church doesn't yet again breathe with both of her lungs at the same time, because I'm fonder of that Greek word mysterion. Here's a good definition: "A mysterion is that to which signs refer; a reality laced with the unseen presence of God." I like this concept better because it directly addresses the bigness of the invisible reality, which extends far beyond the grasp of our sin-stunted senses. Beyond the normal...right?
Wrong. This may sound dumb: Eden was normal. Sin is not normal. Its consequences are not normal. The problem is that we wrongly assume what's normal is what we're used to; and all that stuff that's supposed to lie beyond our senses, well, it may be real in some detached way. But not as real as my fingers or my keyboard. Or at least the bits of them that I perceive. Who knows what aspects of my fingers and keyboard exist on the other side of my personal sin-constricted event horizon? And in spite of sin, reality remains "laced with the unseen presence of God." Laced? More like soaking wet with God.
So let's look at a sacrament: "For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh. This is a great mystery (megas mysterion)." It sure is a mystery, because when my wife and I become one flesh, I know there is more it to than my senses can tell me. I mean physically more to it, not just spiritually. I don't think 'becoming one flesh' is symbolic or figurative. I think we physically become one flesh in a way that would be perfectly obvious to a saint. And that torrent of transcendent fusing while everything still looks the same to this sinner...well, that's the mystery. The merge, the one-fleshing is real. I just...can't...see it.
Likewise, we're literally part of Christ's body. Can you see it? Me neither. But it's not figurative, it's real.
I want to get to baptism in a second, but first let's consider this flag:
It's a symbol of America. But that's all it is. There's no metaphysical connection between the flag and the country. Burning the flag doesn't cause a fire in America. We could swap it out for another flag tomorrow.
But sacraments are different from a flag, and I am not content in class with calling the part of a sacrament that we can see a symbol, and leaving it at that. It's just the visible part of a bigger reality. Consider my wife. If I have a picture of her, that's a symbol. Burning the photo doesn't set my wife on fire. But if I'm looking at my wife- is she a symbol of herself? Oooh. Interesting. Living in the world I'd say no indeed, she is my wife, she is herself, not a symbol. But in the context of an unseen and larger reality, then yes, this bit of her I can sense is a symbol of the aspects of her being I can't sense. Or only sense fleetingly and dimly. If we both wind up in the New Jerusalem, of course there'll be nothing symbolic about her there: it would be The Total Babe for all eternity.
My point is that there are different levels of symbol; and Christians tend to regard the symbolic aspects of sacraments as being like the flag, when they are more like my wife. For example, we use water for Baptism. Some Baptists will tell you Baptism's nothing more than a symbol; doesn't do a thing. The Catholic Church teaches it's a symbol (an outward sign) that signifies what truly happens: sin is washed away. That's consistent with Acts: "Rise and be baptized, and wash away your sins." Pretty clear- but did Luke mean it literally? Does the water actually wash away sin; or does God intervene when the water is poured? That is, on the spirit side, does the water do anything? Dumb old water? I think it does. That is, if the "cloud of witnesses" attends a baptism (and they probably attend them all), they see water wash sin clean off of the person, as plainly as I see dirt washed off of my hands. The wonder of that miracle (and sacraments are miraculous though not dramatic) isn't that it happens at all: it's no big deal for God. The wonder is that the unseen world pokes into the seen one for a few seconds. It's miraculous to us, yes. But it's also normal. It's normal for water to bear this Christ-infused goodness. Human beings, comprising a unity, a continuity, of body and soul, physical and spiritual, can be washed, body and soul, by water. Because like everything else, there are aspects of water we can't see. But then you ask, why doesn't water wash my sins away every time I bathe? Because Baptism effects a permanent spiritual change. Like an egg: one sperm, one time. It's normal. OK...but why don't people get their sins washed away the first time water flows over their heads? Because God leaves it us to intentionally bring a person into his family, and also to assume some responsibility. He does this with making babies; and with making Christians. Water always has the potential to wash away sin, but it happens only through our physical and spiritual cooperation with God's grace.
So think about sacraments as actual, physical, literal conduits of God's power that's not remote, but moves in us and around us. Think comprehensively- like the Catholic Church.
Fun related link here.