1. Exposition

Why must they make flint knives, since this is the Bronze Age?

Joshua 5:3 (ESV)

3 So Joshua made flint knives and circumcised the sons of Israel at Gibeath-haaraloth.

These flint knives (perhaps obsidian)1 would have had a sharpness that is equivalent to anything that a metalsmith could have produced. It is interesting that they must use flint knives given the fact that the men of Israel would have had sharp swords ready for battle. Most likely they had to produce flint knives before they could use them.

Some commentators suggest that the use of flint knives was because religious ceremonies often preserve ancient customs.2,3 Flint knives would then give religious procedures an aura of purity and simplicity since they were not performed with blades fashioned by human hands. More likely, however, the use of flint knives is meant to recall another circumcision that took place in the book of Exodus.4 In Exodus 4:24–26, Moses’ wife Zipporah uses a flint knife to cut off her son’s foreskin and save Moses from God’s wrath, for Moses had neglected to circumcise his child. In Joshua 5, the Israelites had likewise neglected their circumcision. The neglect of circumcision was a sin against the Lord.