ישעיהו ה:כח פירוש: רש״י ואבן עזרא

like flint Jonathan renders: like a rock, similar to צור.

כצר Like flint; comp. צורים flint³⁹A. V., Sharp. (Jos. 5:3); the form of the noun varies.⁴⁰From the same root two nouns can be constructed of different forms, but having the same meaning, like צר and צור flint; there is, according to I. E., no standard for the inflexion of the noun as there is for the verb : all verbs are conjugated after פעל.

and his wheels the wheels of his chariots.