Matthew 19:8 He saith to them -- 'Moses for your stiffness of heart did suffer you to put away your wives, but from the beginning it hath not been so. (YLT)
Mark 10:5 And Jesus answering said to them, 'For the stiffness of your heart he wrote you this command, (YLT)
Mark 16:14 Afterwards, as they are reclining (at meat), he was manifested to the eleven, and did reproach their unbelief and stiffness of heart, because they believed not those having seen him being raised; (YLT)
Deuteronomy 9:27 be mindful of Thy servants, of Abraham, of Isaac, and of Jacob, turn not unto the stiffness of this people, and unto its wickedness, and unto its sin; (YLT)