וְאֶ֙שֶׁד֙ הַנְּחָלִ֔ים אֲשֶׁ֥ר נָטָ֖ה לְשֶׁ֣בֶת עָ֑ר וְנִשְׁעַ֖ן לִגְב֥וּל מוֹאָֽב׃
And the slope of the valleys That inclineth toward the seat of Ar, And leaneth upon the border of Moab.—
Read kabbalistic (mystical) interpretation of Numbers 21:15: and classical mystical sources.