Charles Ellicott Commentary Acts 21:22

"What is it therefore? They will certainly hear that thou art come." — Acts 21:22 (ASV)

The multitude must necessarily come together.—More accurately, in any case, a crowd must necessarily come together. The report of St. Paul’s arrival was sure to spread, and those who heard of it would be eager to see how he acted. Would he ostentatiously reproduce in Jerusalem that living as a Greek with Greeks (1 Corinthians 9:22) of which they heard as his manner at Corinth and Ephesus? The advice which followed was intended to allay the suspicion of the timid, and to disappoint the expectations of more determined adversaries.