Referencing Judges 1:19 - “And the Lord was with Judah; and he drave out the inhabitants of the mountain; but could not drive out the inhabitants of the valley, because they had chariots of iron.”
And Chrysomallon squamiferum, “the only known extant animal that incorporates iron sulfide into its skeleton (into both its sclerites and into its shell as an exoskeleton)”.
I did consider that. Using standard notation, the lowercase “he” as opposed to a capital “He” would mean that Judah is the subject, not God. Nevertheless, the first sentence implies that even with God, Judah was incapable to affect those with iron chariots.