"Like the legs which are useless to the lame, so is a proverb in the mouth of fools"
One of the characteristics of a fool is unapplied truth – wisdom that lies unused in their life. It is just too much trouble to change their convenient way of acting. It is just too much work to become more effective. As the Apostle James says, this is the person who hears the word but does not do it. The natural man/woman is like the person who looks at their image in a mirror and then promptly forgets what they look like because they do nothing about what they see.
This is the Hebrew word masal. The word means to be like or to be comparable to. Proverbs points out relationships between things and truths in juxtapositions to other things to bring out its relevance or need. Proverbs were meant to be easily remembered and actionable. If you know a proverb but do not act in accordance with it, then it has done you no good at all.
The phrase translated "are useless to the lame" is literally "hang down from the lame." This is the great danger of the Western Church. It hears truth and practical information multiple times per week, but there is no change in behavior. Their mechanism for action is broken and is as useless as the legs of a lame man. We must stop hearing truth that we do not apply. Our will to act is not irreparably damaged; it is just so underused that it has atrophied. We must learn to teach in a different way. We must teach in an applicational way that will require and facilitate application. We have now taken the God position in our speaking, writing, and listening where we are the distant observer. Tell me what you are going to say and I will listen and then think about whether I want to do that or not. This grows out of a lack of trust also. The moral failings of some preachers have caused many Christians not to trust the Scriptures nor those who God has called to the ministry.
The point of this proverb is that if you know something is true, then you need to incorporate that into your actions immediately. Do not delay. Find a way in the week that you are presently living in to live out the truth that you have learned.
Another truth from this proverb is that fools know things they do not do. If we were to just do what we know to do, somewhere over 50 percent of our problems would begin to disappear. If you find yourself saying things like, "I really should call that person.” Then call that person. "I really shouldn't say this." Then don't say it. "I really need to get busy on this." Then get busy on it. "I really shouldn't be here." Then get out of there. "Right now, I shouldn't say what I am thinking." Then don't say it and stop thinking about those things and switch to something else. If you find yourself muttering "I want that for all the wrong reasons," then don't go after it. Many times these little leaks of truth that are in us are trying to get us to act consistently with the truth we know. I have learned that when I make these kinds of comments to myself or others that I need to pay attention to, my soul is trying to get my attention before I do something stupid.