John Calvin Commentary Acts 14:13

"And the priest of Jupiter whose [temple] was before the city, brought oxen and garlands unto the gates, and would have done sacrifice with the multitudes." — Acts 14:13 (ASV)

Also Jupiter’s priest. Though Luke does not express with what motive he [this priest] was moved to be so diligent, yet it is to be supposed that, since there was great hope of abundant gain offered, he was moved by covetousness. For he had great hope of gain in the future, if word spread that Jupiter appeared there.

For this opinion would soon have followed: that Jupiter was more delighted in the temple of Lystra than in any other. And as soon as such superstition has once filled the minds of men, they spare no cost to offer sacrifice. The world is indeed naturally inclined to this, but then came the sacrificing priests, who are like fans and bellows.

And there is no doubt that the whole multitude was moved by ambition, to be so eager to offer sacrifice to Paul under the name of Jupiter, so that their city might be more famous and noble. This is why Satan has such great opportunity to deceive, while the sacrificing priests set nets for gain, and the people are delighted to have errors confirmed.