"God is perfect." We talk about God being perfect all the time, but how often do we stop to think about what this means? In fact, for as much as we say that God is perfect, I would dare to guess that we hardly ever even come close to thinking all the way through God's perfection. It is more than we could ever begin to dream.
What does it mean to call something perfect in general? Sometimes we use the word to mean that something is very, very good. Other times we use it with a basically negative type of definition: something that is perfect is something that doesn't have flaws. Still in other cases we use the word only to refer to moral goodness in its purest form, and in this case we often do tend to mix in the negative emphasis of having no flaws. Those who pay a little closer attention in Bible studies might start to pick up "perfect" as meaning something closer to "mature" or "complete, and that is also helpful, but we should be even more clear when we say what it means to call God "perfect."
All of the definitions we just mentioned are true enough when applied to God. God is very, very good. God doesn't have any flaws. God is morally pure, and He is complete in Himself. To truly understand divine perfection, though, we have to see what all of this really comes down to. To say that God is perfect is to say He is completely and entirely active in every kind, type, and way of goodness. The most appropriate definition of perfection for this case is when it means that something lacks nothing, but posseses in reality (not just potentially!) every characteristic which it should have. God, of course, cannot lack anything, and He is in full and active possession of everything He is and can be.
Another way of putting this is to say that God has no wasted potential. We have all seen people who we knew could be or do more than they were. For that matter, we've all failed to be and do everything that we could be, or even just everything that we're supposed to be. God is not like this. On the contrary, He is everything He can be, and He wastes no potential at all. God is fully active, fully engaged, never leaving any "part" of Himself (and we saw He has no parts anyway!) behind or lazy or dormant.
There is more to add, though. Remember that everything God creates represents something or the other about who He is. Like any artist, all God's works have His fingerprints or His signature. Moreover, these are not small traces but are everywhere. Since God is good, and not only good but the source, meaning, and reality of every kind of goodness in all the world, everything good about anything represents something about Him. And this doesn't just mean moral goodness. It means every kind of goodness. If kingfishers are good at catching fish, if spiders are good at spinning webs, if the sunrise makes a good sight for sleepy eyes and if grandma's cookies taste so good you want them every day, all of these good characteristics are what we would call "perfections." And God is behind them all. He invented them. Not only is He their Maker, but He is their truth and reality, The warm, gooey pleasure of a chocolate chip cookie traces back to something in God that the delicious snack reveals in its own tiny way. Obviously God Himself is not literally warm and gooey (which, I should think, would be a very imperfect quality in a deity), but the true goodness and joy to be found in that baked treat is intended to be a tiny picture of God in some way that, when you want the cookie or enjoy the cookie, you're experiencing a desire that ultimate finds satisfaction in God. Everything that is good about cookies is true about God, however differently they apply to Him, and so goes for the rest of the whole created universe.
So when we say that God is perfect, we mean that God is everything He can and ought to be to the fullest and most active extent. We also mean that He has every kind of perfection in Himself, including all of the perfections of everything in creation. From the sunrise to the Great Pyramids to brilliant writing and witty comebacks, the excellence within each of them is a taste, a very tiny but very real sharing, in the perfection of God Himself.