I suppose we all know that as Christians we are meant to grow up, to mature. We begin as infants in the faith and need to develop into adults. The New Testament writers insist that we must all make this transition from milk to meat, from the children’s table to the grown-up’s feast. And yet even though we are aware that we must go through this maturing process, many of us are prone to measure maturity in the wrong ways. We are easily fooled. This is especially true, I think, in a tradition like the Reformed one which (rightly) places a heavy emphasis on learning and on the facts of the faith.

When Paul writes to Timothy, he talks to him about the nature and purpose of the Bible and says, “All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work” (2 Timothy 3:16-17). That word complete is related to maturity. Paul says that Timothy, and by extension me and you and all of us, is incomplete, unfinished, and immature. The Bible is the means God uses to complete us, to finish us, to bring us to maturity.

But what does it mean to be a mature Christian? I think we tend to believe that mature Christians are the ones who know a lot of facts about the Bible. Mature Christians are the ones who have their theology down cold. But look what Paul says: “That the man of God may be complete, equipped for every good work.” Paul does not say, “That the man of God may be complete, knowing the books of the Bible in reverse order,” or “That the man of God may be complete, able to explain and define supralapsarianism against infralapsarianism.” He does not say, “That the man of God may be complete, able to provide a structural outline of each of Paul’s epistles.” Those are all good things, but they are not Paul’s emphasis. They may be signs of maturity, but they may also be masks that cover up immaturity.

When Paul talks about completion and maturity, he points to actions, to deeds, to “every good work.” The Bible has the power to mature us, and as we commit ourselves to reading, understanding, and obeying it, we necessarily grow up in the faith. That maturity is displayed in the good works we do more than in the knowledge we recite. And this is exactly what God wants for us—he wants us to be mature and maturing doers of good who delight to do good for others. This emphasis on good deeds is a significant theme in the New Testament (see Ephesians 2:10; Titus 2:14, etc) and the very reason why God saved us.

This means that spiritual maturity is better displayed in acts than in facts. You can know everything there is to know about theology, you can be a walking systematic theology, you can spend a lifetime training others in seminary, and still be desperately immature. You will remain immature if that knowledge you accumulate does not motivate you to do good for others. The mature Christians are the ones who glorify God by doing good for others, who externalize their knowledge in good deeds.

Of course facts and acts are not entirely unrelated, so this is not a call to grow lax in reading, studying, and understanding the Bible. Not at all! The more you know of the Bible, the more it can teach, reprove, correct, and train you, and in that way shape your actions and cause you to do the best deeds in the best way for the best reason. More knowledge of God through his Word ought to lead to more and better service to others.

But in the final analysis, Christ lived and died so he could “redeem us from all lawlessness and to purify for himself a people for his own possession who are zealous for good works” (Titus 2:14). Knowledge of God and his Word is good. Knowledge of God and his Word that works itself out in doing what benefits others—there is nothing that glorifies God more than that.