John Calvin Commentary Acts 16:21

"and set forth customs which it is not lawful for us to receive, or to observe, being Romans." — Acts 16:21 (ASV)

Ordinances which. They resort to a preconceived argument, to prevent the issue from being disputed. The Papists deal with us in this way even now, saying things like: "This was decreed in a General Council"; "It is an opinion too ancient and common to be called into question"; "Custom has approved this for a long time"; "This has been established by consent for more than a thousand years."

But to what end do all these things lead, if not to rob the Word of God of all its authority? They boast of human decrees, but meanwhile, they leave no place at all for the laws of God. We can see from this passage alone what force these preconceived arguments ought to have.

The laws of the Romans were excellent, but religion depends on the Word of God alone. Therefore, in this matter, we must take great care that human beings are brought into submission, that the authority of God alone prevails, and that He makes all things in the world that are excellent subject to Himself.