What does Proverbs 27:17 mean?

A common method to sharpen steel, or iron, is to use a similar piece of metal. When the two scrape against each other, both pieces are shaped and rough spots are removed. Similarly, two people can interact and help refine each other. Other proverbs note the importance of hearing other people's views (Proverbs 11:14; 18:17; 27:9). Of particular importance is that this lesson implies a constructive level of conflict: the two pieces don't become sharper unless they bump into each other (Proverbs 27:6)! Fellow believers who never challenge or question one another are liable to remain dull.

Numerous biblical examples show the learning value present in relationships. Jesus may have sent His disciples out two by two because each one would sharpen the other's testimony. Mentoring is also a good example of one Christian improving the spiritual life of the other. The apostle Paul mentored the younger Timothy. Furthermore, he encouraged Timothy to mentor others. He writes in 2 Timothy 2:2: "What you have heard from me in the presence of many witnesses entrust to faithful men, who will be able to teach others also." David and Jonathan are a good example of two men who improved each other's lives. Friendship can help two people enjoy a stronger faith and a buoyant spirit. Friends can encourage each other, laugh together, sympathize together, and pray together.

It is crucially important to carefully choose who we "brush up against." A good friend can lead us to self-improvement and greater godliness (Proverbs 12:5; 15:22; 17:17). Ungodly people are likely to lead us towards sin and disaster (Proverbs 13:20; 22:24–25; 23:20).