Acts 21:30

And … ran together This is a proof that what James and the elders had stated was true, the whole Jewish community had been "catechized" on the doings of St Paul among the Gentiles. The least spark set the whole train on fire.

and they took Paul, and drew him out of the temple This rendering hardly does justice to the Greek. Read (with Rev. Ver.) "they laid hold on Paul and dragged him," &c. Their design was probably to get him out of the Temple precincts before they proceeded to further violence. It is clear that all the ceremonies of the Apostle's vow were not yet accomplished, and had they not laid violent hands on him, he might have fled to the altar for safety. That such a murder as they contemplated was possible in Jerusalem at this period we have evidence in the case of Stephen.

and forthwith the doors were shut We need not suppose that any of the Levites, the gatekeepers of the Temple, were of the same mind with the rioters. Their action in closing the gates was only to prevent any profanation of the building by the uproar which they saw to be beginning.