Psalm 68:5 describes God as rokheyv ba’aravot, or “riding upon aravot.” While the second word means “willows” in modern Hebrew and derives from a common Hebrew root with multiple meanings, its interpretation has puzzled exegetes since ancient times. Mitchell First discusses some of the possibilities:
Of all [the word’s usual meanings], the only one that might reasonably fit is “desolate, wilderness area.” Thus, one widespread translation [of the phrase is] “rides through the deserts.” . . . But God as a rider in a desolate area is still an unusual image. More importantly, rokheyv usually means mounting an [animal or vehicle] and not “riding through” something.
In a statement of [the talmudic sage] Reysh Lakish, the aravot were understood to be one of the seven heavens. . . . But aravot does not otherwise mean “heaven” in the Tanakh. . . .
[Another interpretation draws on] Ugaritic, an ancient Semitic language closely related to Hebrew. Ugaritic texts cover many centuries and predate the biblical texts. The discovery of Ugaritic has led to many new understandings of difficult terms in the Bible. Relevant to our context is that the phrase rokeyhv arafot with the meaning “charioteer of the clouds” appears fourteen times in various Ugaritic mythological texts as an epithet for [the] god, Baal. . . . And there are other examples of Ugaritic “p/f” becoming “b/v” in Hebrew. . . . Nowhere else in the Tanakh, however, does aravot have the meaning of “clouds.”