'Hardened' in the Bible

But when some were becoming hardened and disobedient [to the word of God], discrediting and speaking evil of the Way (Jesus, Christianity) before the congregation, Paul left them, taking the disciples with him, and went on holding daily discussions in the lecture hall of Tyrannus [instead of in the synagogue].

“For the heart (the understanding, the soul) of this people has become dull (calloused),And with their ears they scarcely hear,And they have shut their eyes [to the truth];Otherwise they might see with their eyes,And hear with their ears,And understand with their heart and return [to Me],And I would heal them.”’