In my last article, I wrote about the 18th-century pastor John Newton, who showed us that most Christians live with obvious character flaws that ruin both their joy and also their Christian witness. But why do so many Christians live this way?

Our natural virtues, which come from inborn temperament and family nurture—such as our talents, aptitudes, and strengths—are good things. But each has a “dark side.” People with prophetic gifts—great directness, often good at public speaking or writing—can have problems listening to others and taking advice. People with priestly gifts—sensitivity, often good at listening, giving counsel, showing mercy—often can be too concerned to make people happy. They may be cowardly or overly sensitive themselves to criticism. A generous person may also be undisciplined and irresponsible in financial matters. Thus his generosity is really a facet of his too-impulsive character.

Virtues of gifts and temperament have a corresponding “dark side” because our gifts and natural temperament are bound up with the idols that dominate any not heart filled with the gospel of grace. Without a thorough knowledge of the gospel, we look to good things—human approval and relationships, the exercise of power and accomplishment, the control of our environment and self-discipline, the enjoyment of comfort, privacy, and pleasure—and make them into pseudo-salvations. So the person who makes an idol out of human approval may be a sensitive artist, and the one who makes an idol out of power might be a courageous leader. But gifts and temperament in the service of idols—and this is our normal state—always are a mixed blessing. They have a good side—they produce virtuous behavior—but they lead the person into a corresponding sin or vice as well.

As a result, people cannot see their sins because they look only at their virtues. For example, someone may say, “I’m not abrasive, I just speak very directly.” It is true that a direct-speaking person may do good because direct, blunt comments are sometimes needed. But overall the abrasiveness is ineffective, and the person’s boldness and confidence comes to some degree from pride and a lack of love. And for this reason, many (or perhaps most) Christians do not work on the supernatural graces of the spirit that are not natural to us, and that mitigate or eliminate the dark side—the besetting sins—of our nature.

So how can we be shaken out of our lethargy and awakened to our need to grow? Here are some principles I have gleaned from Newton’s letters over the years.

1. Know that your worst character flaws are the ones you can see the least.

By definition the sins to which you are most blind, that you make the most excuses for, and that you usually minimize—are the ones that most have you in their grip. One way we hide our blemishes is that we look at places that our natural temperament resembles spiritual fruit. For example, a natural aptitude for control and self-discipline can be read as faithfulness, and a natural desire for personal approval could look like gentleness or love. Or we mistake a bubbly, sanguine temperament for joy, and a laid-back, phlegmatic temperament for peace. We give ourselves spiritual credit for these things, when actually we aren’t growing spiritually at all. The lack of other fruit shows that real supernatural character change is not happening.

2. Remember that you can’t learn about your biggest flaws just by being told—you must be shown.

There are two ways we come to see our sins and flaws more clearly. One way is that we are shown them by troubles and trials in life. Suffering is “God’s gymnasium”—it reveals our spiritual weaknesses just as a workout reveals physical weaknesses.

We also learn by Christian role models. Sometimes the best conviction comes when you are brought near a person who is living as you should be living. You may not think of yourself as impatient, or abrasive, or over-sensitive until you are brought into close proximity to someone much more patient, irenic, and content. We should make use of these opportunities to grow. They are painful—even being near very holy people can be uncomfortable. But at such times, when we most feel the need for grace, that we find God’s grace most desirable.

3. Be willing to listen to correction and critique from others.

We just said that no one ever learned about his or her sins by being told. We have too many layers of self-justification to grow without hard knocks. But in addition, as a complement, we need critique and accountability from brothers and sisters.

There are at least two kinds. First, you can create your own Hebrews 3:13 community. Hebrews 3:13 says we are to “exhort one another daily” so we are not “hardened by the deceptiveness of our sin.” Take some other believers that you trust and give them “a hunting license” to talk to you about where you need to grow.

Second, don’t forget the “Balaam’s ass” principle. You must learn how to profit from criticism even given by people who are badly motivated, or whom you don’t respect. Even if only 20 percent of what they say is true, it may be God speaking to you.

But, you may ask, how do we actually make changes once we see where we need to change? We will look at that in the next article.

This article originally appeared in Redeemer Presbyterian Church’s monthly Redeemer Report.