Numbers 21:2-6

²And Israel vowed a vow to the Lord, and said, If thou wilt deliver this people into my power, I will devote it and its cities to thee.

³And the Lord hearkened to the voice of Israel, and delivered the Chananite into his power; and Israel devoted him and his cities, and they called the name of that place Anathema.

⁴And having departed from mount Or by the way leading to the Red Sea, they compassed the land of Edom, and the people lost courage by the way.

⁵And the people spoke against God and against Moses, saying, Why is this? Hast thou brought us ought of Egypt to slay us in the wilderness? for there is not bread nor water; and our soul loathes this light bread.

⁶And the Lord sent among the people deadly serpents, and they bit the people, and much people of the children of Israel died.