“As a result, people brought the sick into the streets and laid them on beds and mats so that at least Peter’s shadow might fall on some of them as he passed by.”
Peter wasn’t the person announcing a new ministry style, that of shadow healing.
God hadn’t spoken to the Church prophetically telling them that a day would come when shadow healing would be the way to go.
This was the people’s decision. It was based on Jewish superstitions of which there were many. For example, why does Jesus spit on a man’s eyes in order to heal him? It was because of the superstition of the healing properties in the spit.
But even in the Roman culture the people held to superstitions. The statues of the gods were not just images as we would think, they were actually the gods. So if you approached the statue you were before the god itself. The shadow of the statue carried the presence of the god.
So this is the people using their superstitious minds for their benefit, hoping for healing.
Luke doesn’t record whether or not people were genuinely healed. Neither does he repeat this peculiar practice. Though later he would write of Pauls handkerchief having healing powers, again a superstition of the people.
If we presume people were healed under Peters shadow then it would indicate the willingness of God to move into a person’s life and their beliefs no matter how weird and fanciful they are and lovingly heal the person. God healed simply out of love without conditions, taking the risk that people would not follow Him even after they were healed.
Friends we have a loving God who loves people more than we do.