Exodus 4:25
Then Zipporah took a flint and cut off her son's foreskin and touched Moses' feet with it and said, "Surely you are a bridegroom of blood to me!"
Joshua 5:2-3
At that time the LORD said to Joshua, "Make flint knives and circumcise the sons of Israel a second time."
Genesis 17:14
Any uncircumcised male who is not circumcised in the flesh of his foreskin shall be cut off from his people; he has broken my covenant."
2 Samuel 16:7
And Shimei said as he cursed, "Get out, get out, you man of blood, you worthless man!