What does ‘iron sharpens iron’ mean?

TL;DR:

“Iron sharpens iron” (Proverbs 27:17) means that people grow wiser and more effective when they challenge and encourage one another in close fellowship. In the church, this sharpening happens as believers live out the “one another” commands, helping each other grow to be more like Christ through love, correction, and support.

what does the bible say?

“As iron sharpens iron” is derived from Proverb 27:17, which gives a general truism that is similar to the idea that “two heads are better than one.” That is, just like two pieces of iron both get sharper as they are rubbed together, so also do two people grow in wisdom as they work together and share insights. Iron sharpening iron is often used inside the church to mean something similar but specific to believers. The phrase is used to mean that believers are fellowshipping in such close proximity that they are like iron rubbing up against iron. Scripture exhorts (encourages) believers to help other believers grow in nearly 60 “one another” passages. In each one, believers are told to do something for other believers (pray, love, encourage, rebuke, etc.) such that both are sharpened during the process. The sharpening that happens in relationships means that each person grows in wisdom and character through the other’s application and demonstration of Scripture in their contexts.

from the old testament

This phrase “iron sharpens iron” comes from Proverbs 27:17, which says, “Iron sharpens iron, so one man sharpens another.” This proverb illustrates how wise men “sharpen,” that is, grow wiser. When iron blades are rubbed together, each becomes sharper and more effective. Similarly, when people come together, they sharpen one another by sharing insights and thoughts.
Ecclesiastes 4:9–12 expresses something similar. It reads, “Two are better than one because they have a good return for their labor. For if either of them falls, the one will lift up his companion. But woe to the one who falls when there is not another to lift him up.”

from the new testament

Though the phrase “iron sharpens iron” is not found in the New Testament, the Proverb is often quoted within the context of church and believers’ relationship with other believers. Believers sharpen one another as they live the Christian life together.
The New Testament is filled with instructions about how believers are to live the life of faith together. They are to do good to one another (Galatians 6:10), bear one another’s burdens (Galatians 6:2), forgive one another (Colossians 3:13), restore one another (Galatians 6:1; James 5:19-20), submit to one another (Ephesians 5:21), encourage one another (1 Thessalonians 5:11), admonish and exhort one another (Colossians 3:16; Hebrews 3:13), pursue peace and build up one another (Romans 14:19), and stir one another to love and good deeds (Hebrews 10:24-25).
When believers are in contact with other believers, they are like iron sharpening iron. Each believer becomes sharper in his understanding of Scripture and more like Christ. He comes to know God better and to more effectively carry out the good works for which he has been made (Ephesians 2:10).

implications for today

Scripture never speaks about believers disconnected from a local body, living separate from other believers. Instead, believers are called to be in fellowship with other believers. All believers are expected to be active participants in their local church because we are the body and family of Christ.

Indeed, there are nearly 60 “one another” passages in the New Testament that describe how we are to help and shape other believers (and to be shaped by them!). Obeying those passages requires up close, sharpening fellowship. Since these passages are a major focus of what Christian life is to be like, they show just how important fellowship is to God!

A brief list of what we should each be doing is: loving (John 13:34–35), serving (Galatians 5:13), forgiving (Ephesians 4:12), bearing (Colossians 3:12), encouraging (1 Thessalonians 5:11), submitting (Ephesians 5:21), praying (James 5:16), admonishing (Romans 15:14), and speaking and singing psalms and songs (Ephesians 5:19). All of that is to be done to and for other believers! As we live this way, we grow to be more like Christ and show what Christ is like. In short, we become like “iron sharpening iron.”

understand

Proverbs 27:17 teaches that just as iron sharpens iron, so people grow in wisdom and Christlikeness through intentional relationships.
Believers are called to live out the “one another” commands of Scripture, which exemplifies iron sharpening iron.
True spiritual sharpening happens in the context of active, committed relationships within the body of Christ, not in isolation.

reflect

How have close relationships with other believers helped you grow in wisdom or character?
How are you responding to believers sharpening you, whether lovingly challenging, correcting, or encouraging you in your walk with Christ?
Which “one another” command do you find hardest to live out, and why might that be?

engage

What does it look like in real life for believers to “sharpen” one another in the church today?
What role do we play in having the church be a place where real sharpening—through love, correction, and support—actually happens?
Why is it important to practice the “one another” commands, which sharpens us, in committed relationships rather than just occasional fellowship?