Acts 19:9
But some of them became obstinate (skepthēmi, to be hardened or stubborn); they refused to believe and publicly maligned the Way — Before the crowd, he left the synagogue and took the disciples with him, arguing daily in the lecture hall of Tyrannus — The obstinate resistance (hardening of hearts) forces the pivot: Paul withdraws formal synagogue space, establishing independent teaching venue. The 'Way' (hē hodos) denotes early Christian self-identification.