How is it that Peter could approach the lame man at the gate named "Beautiful" and give him what he has (healing) if Peter did not know God's will in respect to healing? He said, "Rise up and walk!" Now, you might say this was something only an apostle could do, but lets read the verses in context and notice something Peter said about God, the Father.
Acts 3 King James Version (KJV)
3 Now Peter and John went up together into the temple at the hour of prayer, being the ninth hour.
2 And a certain man lame from his mother's womb was carried, whom they laid daily at the gate of the temple which is called Beautiful, to ask alms of them that entered into the temple;
3 Who seeing Peter and John about to go into the temple asked an alms.
4 And Peter, fastening his eyes upon him with John, said, Look on us.
5 And he gave heed unto them, expecting to receive something of them.
6 Then Peter said, Silver and gold have I none; but such as I have give I thee: In the name of Jesus Christ of Nazareth rise up and walk.
7 And he took him by the right hand, and lifted him up: and immediately his feet and ankle bones received strength.
8 And he leaping up stood, and walked, and entered with them into the temple, walking, and leaping, and praising God.
9 And all the people saw him walking and praising God:
10 And they knew that it was he which sat for alms at the Beautiful gate of the temple: and they were filled with wonder and amazement at that which had happened unto him.
11 And as the lame man which was healed held Peter and John, all the people ran together unto them in the porch that is called Solomon's, greatly wondering.
12 And when Peter saw it, he answered unto the people, Ye men of Israel, why marvel ye at this? or why look ye so earnestly on us, as though by our own power or holiness we had made this man to walk?
13 The God of Abraham, and of Isaac, and of Jacob, the God of our fathers, hath glorified his Son Jesus
How does a healing glorify Jesus Christ, the Son of God? How did God glorify His Son through an act of healing? It very well may be that Christ through His bloodshed and suffering purchased it. Notice in verse 6 that the command to rise up and walk was done so "in the name of Jesus..." and it is by that authority healing occurs. Why? Jesus is Lord.