Iron was a metal that was naturally present in Israel, even though it took the Israelites some time to learn how to work it (1 Samuel 13:19-21). Iron requires a lot of heat and hammering to produce a usable material; however, iron has to be protected or it will rust, and eventually the object made of iron will be useless and destroyed. Iron was used for tools made for cutting and digging because of the hard, sharp edges that could be made with iron.
Our “iron things” (some of our natural character traits) come from inside of us and can represent some of our toughest obstacles to overcome. Proverbs 27:17 (as iron sharpens iron) tells us why a person may rub us the wrong way, God wants our hard areas worked on and that is done by having to work with other people’s hard areas. An example in David’s life is his relationship with his brothers (1 Samuel 17:28+29). As an over achieving little brother who had killed a lion and a bear, and had been in the king’s service as a harp player he apparently allowed these accolades to develop as a sore spot with his brothers. Our own attitudes can be a hard, sharp cutting point in our life. People will view them as either our greatest asset or our biggest bane, but yielding this “iron” to God’s testing and use is really what is important. These “iron areas” will either be protected and maintained in us, rust and cause real problems, or sharpened and gotten rid of.