en_tn_lite_do_not_use/2ch/06/23.md

bringing what he has done upon his own head

To bring someone's conduct on him represents punishing him for his bad conduct. Alternate translation: "punishing him as he deserves" (See: rc://en/ta/man/translate/figs-metaphor)

upon his own head

Here the "head" refers to the whole person. Alternate translation: "on him" (See: rc://en/ta/man/translate/figs-synecdoche)

give to him according to his righteousness

"give him what he deserves because he is innocent"