'Stubborn' in the Bible

“You stiff-necked and stubborn people, uncircumcised in heart and ears, you are always actively resisting the Holy Spirit. You are doing just as your fathers did.

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].

So then, He has mercy on whom He wills (chooses), and He hardens [the heart of] whom He wills.