كُونُوا حِجَارَةً أَوْ حَدِيدًا
Be stones or iron.
“Be stones or iron” exemplifies ihānah, humiliation. The expression derides the addressees’ assumption that resurrection is impossible; it is not literally instructing them to transform themselves into stone or iron.
Contrast taskhīr, which centers on imposed transformation, with ihānah, which centers on belittling and exposing the weakness of a claim. Morphology alone cannot mark the difference.