As we grow in our knowledge of biblical doctrine, and as we expand the boundaries of what we know under the heading of a “biblical world view,” we have to be careful about one of the oldest traps in Christendom.
Knowledge puffs up, St. Paul tells us, but love builds up. Graduate school is not the place where you get to forget all that you learned in kindergarten. All the Sunday School basics apply to everyone here, all day long, every day.
Tell the truth. Be honest. Be kind. Let others go first. Work hard. Respect your parents.
One of the first lies that sin tells us is that it is possible to grow past these things. We are told that maturity means that the basics don’t apply anymore, and we tend to look down on those poor saps who are still paying attention to them.
There really is a great problem in the church with overscrupulous pietists, and there are legalists who go about with dour looks, looking for things to disapprove of. But it will not do, in response to this, to start calling people pietists, simply because they love their neighbor more than you do.
Pietism makes a great show of obeying man-made standards, all the while giving way to great impiety. When you are liturgically scrupulous and you are fornicating, you are a pietist. When you attend worship faithfully but yell at your children, you are a pietist. But true piety is something else—piety is simply a very practical love for God and neighbor in all things, great and small.
This is basic, and it is very practical. And we never outgrow it.