…But Peter said, “Silver and gold I do not possess, but what I have, this I give to you—in the name of Jesus Christ the Nazarene, walk!” And taking hold of him by the right hand, he raised him up, and immediately his feet and ankles were made strong.
Or why are you staring at us, as if by our own power or godliness we have made him walk? The God of Abraham … has glorified his servant Jesus.
…And on the basis of faith in [Jesus’] name, [Jesus] name has made this man strong, whom you see and know, and the faith that is [sovereignly given] through [Jesus] has given him this perfect health in the presence of you all.
…Therefore repent and turn back, so that your sins may be blotted out, so that times of refreshing may come from the presence of the Lord.
…You are the sons of the prophets and of the covenant that God ordained with your fathers, saying to Abraham, ‘And in your offspring all the nations of the earth will be blessed. 
It is irrelevant to our point, if Peter is referring to himself or the man, regarding who God sovereignly gave the faith to. Peter says Jesus sovereignly gave the faith in His Name to be healed. This is spoken in the exact same way predestination is spoken of, with regards to salvation. For example, Acts 16:14, (LEB) “And a certain woman named Lydia from the city of Thyatira, a merchant dealing in purple cloth who showed reverence for God, was listening. The Lord opened her heart to pay attention to what was being said by Paul.” See also Romans 9.
On ultimate level ontology God is always the author, just as in this case with healing or salvation. However, the ultimate level ethics is what God commands, and so, even if God decrees and causes person “x” to not accept the gospel promise, they will be judged, not on what God caused but by what God has commanded. God has commanded all to repent and believe. God decreed and directly hardened Pharaoh’s heart, but judged the Pharaoh, not on His causality, but on His command to let His people go. The same is with healing. God has commanded us to be healed, James 5, John 15:1-16. It is not an option. On the ultimate level ontology, even if God has caused you not to have faith to accept His promise for healing, you will be ethically accountable by God’s command, for you to have your own faith and get healed. The more someone claims it is God’s Will for them not to believe in His promises, the more they claim they are a reprobate.
Peter does not say, “by the powerful faith of an apostle.” No, rather he makes two points about the healing. First, Jesus gave the faith, and then faith was used. Second, Peter then connects these to the blessing of Abraham, “the covenant that God ordained with your fathers, saying to Abraham, ‘And in your offspring all the nations of the earth will be blessed.’” That is, this is not a sign, but God being faithful to His old promise. A sign is to give assurance that you will fulfill your covenant, or it might be to point to who, or how you will do it. This is painfully different from that act of actually doing what you promise. Peter uses this healing to tell those in the Temple to believe in Jesus name for redemption, and then, be refreshed. The context is this man’s healing; and so, being refreshed is not less than healing. This forgiveness of sins and being refreshed, like this man’s healing, are both put under God faithfully doing His covenant to Abraham. This is like what Peter said in earlier Acts 2 in his sermon. Similar in that the gospel is more than forgiveness of sin. God has predestined some to be baptized in the Holy Spirit, as many as God will sovereignly call. Thus, Peter’s admonishing for them is to repent and be saved, so that then, they can receive what is so important, the promised baptism of the Spirit.
Peter seems to be echoing what He learned from Jesus, when He healed the bent-over woman on the Sabbath (Luke 13:16 ). Jesus said, because she was a daughter of “Abraham,” that it was “necessary” to heal her. Not a sign of the Abrahamic covenant, but a fulfillment of it.
Paul also connects, in Galatians 3, that a fulfillment of the Covenant of Abraham includes the Holy Spirit and miracles. Also, everything that has been said, had nothing to do with the “gits of the Spirit,” in Corinthians 12-14. The gifts are an extra mode for God’s blessings, that are spoken of in a minority in the Scripture. Faith for healing and miracles is mostly connected by Scripture to God’s promise to Abraham and faith. Thus, what has been said is God being His normal Self, by being faithful to His covenant to Abraham. Jesus gives everyone categorical access to this promise, by faith in His name.
Going back to Peter, the lessons to learn here are that the Apostles are nothing special in regard to healing and miracles. The Apostles anchor these healings, miracles and baptism of the Spirit to the promise of Abraham. Peter, as does Jesus and Paul, makes this connection by faith in God’s faithful promise keeping. Abraham was the father of faith. And so, Paul says in Galatians 3, that those who have faith in Jesus show themselves to be true children of Abraham. Peter connects the forgiveness of sins and healing to this “blessing of Abraham.” Both are about God doing what He said He would perform to Abraham, and not a sign that He will do what He said to Abraham.
God sovereignly makes promises and he sovereignly keeps them. Jesus performs the Mosaic covenant in perfection, in our place, for us. It is true that we do not merit God’s blessings by working for them. The reason is twofold. God gave them as a free promise of grace to Abraham. Secondly, Jesus did the obedience of the Mosaic law, in our place. This includes both taking away the curses, but also the blessings promised for such perfect obedience. All the requirements for obedience to acquire blessings is done by Jesus the righteous. Jesus grafts us into the Abrahamic promise of blessing, and fulfills the Mosaic law for us. This is great news. What is left, is faith. Faith in the good things God has so kindly done for us.
As Vincent Cheung often says, Jesus and not the Apostles, define eras. Who cares, if the Apostles are gone? What do they have to do with me receiving God’s promise through Jesus’ name? Want to see what real man-centeredness looks like? Then focus on men like the apostles. Define Jesus’ blood bought gifts by men. People define ages by the death of the apostles, not because the Scriptures do, but because they are so habitually man-centered, they cannot see ages in any other way, except by man. The Apostles never made it about themselves; rather, they made it about Jesus and faith in Him.
Jesus is still here. He has been resurrected. He is at God’s right hand. He is ready to pour out the promised Holy Spirit, for those who have faith. He is ready to refresh with healings and miracles. The religionist back in the day decorated the tombs of the prophets, whom they never believed. But it made them feel good and look good to others. Men focus on other men who are gone and dead, but the true sons of the covenant focus on the One who made it. And He is still here. Thus, His name and faith in His Name, still stands for anyone who will have it. Do not behave like mere man-centered mortals. God is the one who made the covenant. He has kept it. He will keep it. Faith gives you direct access to the throne room of Heaven, before the Father and the Son. Before the One, who loved you when still a sinner. He already sees you as and calls you a son. Let no one cheat you of your reward, that was given to you by the precious blood of Jesus Christ.
Peter was focused like a mere mortal on the stormy waves. He sank because of this. Why does this matter? Is there calm waves? Why does this matter? Is there stormy waves. Who cares! Jesus is the deciding factor. And He is still here. Since you are a new creation, then you are already a walking miracle. That is, you are walking on the water, but it never had to do with the water or you. Jesus’ power, and faith in Him is the reason you are walking on them. Calm or stormy, apostles or no apostles, it does not matter. Even for those who have been sinking for a long time with their man-centered view, and have been dragging countless others down with them, Jesus is still there; and so, even someone as despicable as you, if you would have faith in His Name, can still find salvation and refreshment. Why? Because it has always been about Him. He defines ages, and times. And today is the right time, because He is still here.
Redemption, healing, miracles and refreshment are not signs of the covenant, but God doing the covenant; because of this, if you have faith, then they are still guaranteed.
 Acts 3:6,12-13,15,19-20,25. (LEB) -added by author
 See Vincent Cheung. “I Will Never Leave You,” Sermonettes Vol. 7, chapter 4. 2012.
See also “The Edge of Glory,” Sermonettes Vol. 9, chapter 19. 2016