Numbers 21:13-17

From there they journeyed and camped on the other side of the Arnon, which is in the wilderness that comes out of the border of the Amorites; for the Arnon is the border of Moab, between Moab and the Amorites.

For that reason it is said in the Book of the Wars of the Lord, “Waheb in Suphah, And the wadis of the Arnon,

And the slope of the wadis That extends to the site of Ar, And leans to the border of Moab.”

From there they continued to Beer, that is the well where the Lord said to Moses, “Assemble the people, that I may give them water.”

Then Israel sang this song: “Spring up, O well! Sing to it!