There's a huge difference in Peter after he receives the Spirit.
Before he's enthusiastic, loves Jesus, but is still weak in the flesh and not really understanding much.
Afterwards, his very shadow heals people.
14And all the more believers in the Lord, multitudes of men and women, were constantly added to their number, 15to such an extent that they even carried the sick out into the streets and laid them on cots and pallets, so that when Peter came by at least his shadow might fall on any one of them. 16Also the people from the cities in the vicinity of Jerusalem were coming together, bringing people who were sick or afflicted with unclean spirits, and they were all being healed. [Acts 5]