the iron entered into someone's soul

the iron enters (into) (someone's) soul

Someone succumbs to depression, bitterness, or despair from being imprisoned or treated poorly. After just a year of that horrible marriage, the iron entered into her soul, and she became embittered and disillusioned to the entire notion of romantic love. I could feel the iron entering my soul with each day that passed working for that horrible man.

the iron entered into someone's soul

someone became deeply and permanently affected by imprisonment or ill-treatment. literary

This expression comes from a phrase in the Latin Vulgate version of the Bible, ferrum pertransit animam ejus , a mistranslation of the Hebrew which literally translates as ‘his person entered into the iron’, meaning ‘he was placed in fetters’.