Proverbs 27:17 reads, "As iron sharpens iron, So a man sharpens the countenance of his friend."
Many quote this scripture to say you are using abrasion to smooth off each other's rough edges. A deeper look shows that may not be what the proverb is saying.
Some tend to see this scripture in the context of sharpening a sword or an ax. What if it is talking about sharpening knives?
When a knife is straightened by another knife, it is done with precision. It will also burnish or brighten the blade. If you just go at it haphazardly, it has the opposite effect.
If you weary others with your constant stabs and never giving credence to their point of view, you will soon run out of people to have discussions with you. It dulls rather than sharpens.
From Knife Maintenance and Sharpening:
"Blades are damaged primarily by buckling—compressive force, from being pressed into a hard object, such as bone, ice, or a hard cutting board—and by bending, from sideways pressure. Both of these tend to roll the edge of a blade, due to metal's ductile nature."
From The Knife Sharpeners Guide:
"The finest level of sharpening is done most frequently, while the coarser levels are done progressively more rarely, and sharpening methods differ between blades and applications.
For example, a straight razor used for shaving is stropped before each use, and may be stropped part-way through use, while it will be fine sharpened on a stone a few times per year, and re-ground on a rough stone after several years.
By contrast, a kitchen knife is steeled before or after each use (and may be steeled during heavy use, as by butchers), and sharpened on a stone a few times per year.
A knife that has become dull because of nicks in the blade needs a lot more than being steeled. It then has to go for a procedure that grinds the edge of it off—usually a stone—but sometimes sandpaper. This too needs to be done with expertise, or you just grind away your knife and never get a sharp edge.
Even under normal use, a knife's edge will roll a little. When you take two knives and move them together, as you sometimes see chef's do, you get those edges to become straight again. It takes a lot to put a nick in the blade of a knife and usually happens because of improper handling."
The concept of iron sharpening iron means both sides benefit.
Be an effective listener. It increases your ability to help others.
Consider this proverb: "The one who has knowledge uses words with restraint, and whoever has understanding is even-tempered" (Proverbs 17:27).
Sharpening the countenance of a friend
What about the second part of Proverbs 27:17: "So a man sharpens the countenance of a friend"? How would you "sharpen" the face of your friend?
The definition of the Hebrew word for "sharpen," chadad, can mean "sharpened and furbished" (polished to make it bright). It also means to make keen or sharp. A keen edge on a knife stays sharp through many uses and is the type of knife a chef will look for.
Ask yourself if what you are saying will polish (brighten) the countenance of a friend, or if it tear down your relationships. Will it help your friend stay sharp, or does it chip away from them?
Do you seek to find a way to discredit whatever they say so you can continue in your own opinion?
If you are not careful about how quickly you go when you sharpen, you will make the blade too hot and it will lose its temper. Tempering gives a correct balance of toughness and hardness. Without it the blade is brittle and full of stress.
Are your words causing bitterness and stress, or are they edifying and good fellowship?
Above all, respect each other and listen with empathy—it is not a battle of words.
On the other hand a friendly banter where neither side feels threatened can be beneficial. It should edify and strengthen understanding, making you keen in the handling of scriptures.
An example I feel illustrates iron sharpening iron happened when I had a discussion with a friend about whether Philippians 2:3 is saying you should see everyone else as better than you when we are told in another scripture to not compare ourselves to others, but to Christ. They postulated that this scripture is actually talking about showing deference. Maybe it is about taking the backseat to others and not seeking to push yourself always in the forefront. It starts off by saying not to do something seeking vainglory, and it compares to Christ who became a servant. I felt enlightened by the discussion and encouraged. We don't have to constantly beat ourselves down and look to others to see what they are doing better than we are, but rather to treat others with respect and service regardless of who they are or their status in this life. I felt this gave a new application to the scripture than the way it is commonly seen and was perhaps a better explanation. Jesus Christ was the son of God, but He chose to be a servant, and we are to emulate Him.
We all come from a lot of differing backgrounds and strengths. One of the admonitions to us is to choose our words carefully and not cause offense. Don't just let words fly out of your mouth, or your pen, because they come to mind, but study so you can have a deeper understanding and can sharpen the countenance of your friends.