In Luther’s 95 theses, he observes, “Our Lord and Master Jesus Christ, when He said Poenitentiam agite, willed that the whole life of believers should be repentance.”
I think that Luther is correct here. For instance, in Romans 12:2, Paul summarizes the Christian life as being “transformed by the renewing of the mind.” Luther’s thought is that the entire Christian life is looking to God’s revelation in Christ, looking to ourselves as sinful and in need of grace and mercy, and transforming our minds on the basis of that revelation.
With this in mind, I wish to look at true self-knowledge and self-deception.
Coming to know ourselves in a true way is central to the Christian life. It is also central to becoming successful in other endeavors as well. The problem with coming to this knowledge is a frequent failure to consciously admit what we really know to be true. This is a form of self-deception.
For instance, one of my legs is shorter than the other. As I’ve gotten stronger in the gym this leg geometry issue has become uncomfortable.
For years I just thought, “Well, it’s not that bad. In fact, I can totally deal with it.” But in reality the different is significant enough that affects my posture and contributes to some sharp pain in a small area in my lower back.
I finally admitted that I have this problem and went to a cobbler and got some hard crepe added to my squat and dead lifting shoes.
My back is slowly getting used to having even hips in the squat. I’m not as strong as I was despite being functionally “healed” by my change of mind on the matter. But I’m slowly building back up and squats and deadlift no longer make my hip joints feel weird or bad.
With respect to spiritual growth, similar failures to acknowledge the actual state of our souls can cripple us as we grow in other areas. Similarly, admitting the truth about ourselves, “I really am a wrathful/lustful/arrogant/murderous/selfish/failing/fooling person…” can feel like a major regress. But living with frequent failures and near misses with respect to our most embarrassing or incriminating impulses and then covering them with phrases like, “I blew it” or “God is strong in my weakness” is a copout if we think of repentance as the whole of the Christian life. Repentance involves, as I mentioned above, comparing ourselves to the revelation of God in Christ.
So, coming to self-knowledge has benefits. But it is difficult just like coming to true knowledge of this or that field of study.
In the case of my leg-length discrepancy, I had to actually become weaker temporarily to train my body safely. A similar problem could come to somebody who finally owns the fact that they are greedy and in significant debt. The art of living justly and graciously with regard to finances might require that they become way less generous until they pay of their debts (because giving money away that you owe to somebody else is certainly not Christlike or good).
Because self-knowledge can be so difficult or even painful, we have tremendous incentive not to gain it. This reticence may even lead us to not even have a system in place to gain self-knowledge. Thankfully, the Bible and plain reason give us several methods to gain self-knowledge:
- Admit that your wisdom is apt to be flawed
1Co 3:18 Let no one deceive himself. If anyone among you thinks that he is wise in this age, let him become a fool that he may become wise.
1Co 8:2 If anyone imagines that he knows something, he does not yet know as he ought to know.
- Compare Your Life to Scripture’s Moral Ideals
Jas 1:23-25 For if anyone is a hearer of the word and not a doer, he is like a man who looks intently at his natural face in a mirror. (24) For he looks at himself and goes away and at once forgets what he was like. (25) But the one who looks into the perfect law, the law of liberty, and perseveres, being no hearer who forgets but a doer who acts, he will be blessed in his doing.
- Accept Criticism
Pro 10:17 Whoever heeds instruction is on the path to life, but he who rejects reproof leads others astray.
Pro 12:1 Whoever loves discipline loves knowledge, but he who hates reproof is stupid.
- Be a part of a group wherein you can frankly discuss your sins, failures, and flaws
Pro 27:17 Iron sharpens iron, and one man sharpens another.
Jas 5:16 Therefore, confess your sins to one another and pray for one another, that you may be healed. The prayer of a righteous person has great power as it is working.
- Spend time in silence
From personal experience, spending time in silence is a powerful way to have the tape of your life replay in your mind. If you approach this with the mindset that “I am what I think and what I do,” you’ll find that you might be a lot worse than you are. This is probably not a good discipline for people who struggle with depression or melancholy. But if you want to assess yourself, then it is hard to find a better method.
This can come from all of the previous methods. You can write your personal resolutions and your assessment of how you met them or did not.
One of my old karate instructors said, “When presented with two standards, always choose the highest.” Self-deception is easy. Self-knowledge is hard. But the way of self-knowledge allows us to deny ourselves in the truest way. And self-denial under Christ’s guidance is the only way to the life of rest that he promises:
“to step with Jesus into the path of self-denial immediately breaks the iron-clad grip of sin over human personality and opens the way to a fuller and ever fuller restoration of radical goodness to the soul. It accesses incredible, supernatural strength for life.”
 Observe that while Paul criticizes the “wisdom of this age” Paul never equates that with the wisdom of Proverbs and Ecclesiastes. The wisdom of “this age” appears to be the wisdom of making non-Christian ideals ultimate such as riches, knowledge, rhetoric, long life, etc.” These are all goods to seek in the Bible, but they are not to be sought as ultimate or final goals. Instead the Christian who sows and spins for food and clothes is to nevertheless “seek first the kingdom of God.” So don’t take Paul’s warnings as a censure on being wise. Paul actually says that you can become wise if you first admit your foolishness. In fact, in 1 Corinthians 3:19 you see that God’s wisdom (what is revealed in the Old Testament and the gospel) is still good. This is why we shouldn’t boast in our favorite teachers as though they make us superior to other Christians. Instead, we should boast in the Lord.
 In Christ this is not all you are, but you are not less than what you think and do.
 Dallas Willard, Renovation of the Heart: Putting on the Character of Christ (Colorado Springs, Colo.: NavPress, 2002), 75.