At that time the Lord told Joshua, “Make flint knives and circumcise the Israelites once again.” ¹ 

So Joshua made flint knives and circumcised the Israelites on the Hill of the Foreskins. ¹ 

Their arrows are sharpened, and all their bows are prepared. ¹  The hooves of their horses are hard as flint, ²  and their chariot wheels are like a windstorm. ³ 

But Zipporah took a flint knife, cut off the foreskin of her son and touched it to Moses’ feet, ¹  and said, “Surely you are a bridegroom of blood ²  to me.”

and who brought you through the great, fearful desert of venomous serpents ¹  and scorpions, an arid place with no water. He made water flow ²  from a flint rock and

I have made your forehead harder than flint – like diamond! ¹  Do not fear them or be terrified of the looks they give you, ²  for they are a rebellious house.”