'Flint' in the Bible

Zipporah took a flint knife, cut off her son's foreskin, and touched Moses' feet with it, saying while doing so, ""because you are a bridegroom of blood to me."

He mounted him on a high place above the earth, feeding him from the produce of the field. He nourished him with honey from the rock and with oil from the flint rock,

At that time the LORD told Joshua, "Make for yourselves some flint knives and circumcise the Israelis who haven't been circumcised yet."

So Joshua made some flint knives and circumcised the Israelis at Gibeath-haaraloth.

"Using a flint, he thrusts his hand, overturning mountains by the roots.

Their arrows are sharp, all their bows ready for action. Their horses' hooves seem like flint, and their chariot wheels spin like a whirlwind.

For the Lord GOD helps me, so I won't be disgraced. Therefore I've made my face like flint, and I know that I won't be put to shame."

I'm making you harder than flint like diamond! So you are not to fear them or be intimidated by how they look at you, since they're a rebellious group."