John Calvin Commentary Acts 19:11

"And God wrought special miracles by the hands of Paul:" — Acts 19:11 (ASV)

No small miracles. He calls miracles virtutes or powers, after the common custom of the Scripture, which were testimonies of the extraordinary power of God. And he shows that Paul’s apostleship was set forth with these ensigns, so that his doctrine might have greater authority. For it is a common saying that wonders and signs are shown by the hand of men.

So the praise for them is ascribed to God alone as the author, and man is only the minister. And to further amplify the miracles, he says that handkerchiefs and aprons were brought to the sick, and as soon as the sick touched these, they were healed.

It is well known for what purpose Paul was given such power: namely, that he might prove himself to be a true apostle of Christ, that he might cause the gospel to be believed, and that he might confirm his ministry. And here it is appropriate to recall those things we have discussed before concerning the lawful use of miracles.

Since God healed the sick with Paul’s handkerchiefs, this served the purpose that even those who had never seen the man might nevertheless reverently embrace his doctrine, though he himself was absent. For this reason, the Papists are all the more foolish, who distort this account to support their relics, as if Paul sent his handkerchiefs so that people might worship them and kiss them in their honor. As in Popery, they worship Francis’s shoes and mantle, Rose’s girdle, Saint Margaret’s comb, and similar trifles.

Indeed, rather, he chose very simple things, so that no superstition should arise because of their cost or splendor. For he was fully determined to keep Christ’s glory intact and undiminished.