steel one's heart against

Idioms and Phrases

Also, harden one's heart . Suppress one's feelings for, as in He finally steeled his heart against them and refused the loan , or You'll just have to harden your heart and tell them the truth . This metaphoric idiom transfers making something hard to rendering oneself insensible or unfeeling. Versions of it date from the late 1500s. Also see heart of stone .