One knows authentic healing still occurs because people are still becoming believers. Jesus, Himself said: "...
signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover." Mark 16:15-18
Jesus' statement is confirmed in the Book of Acts. The record provides illustration of Jews, Gentiles, and Samaritan's speaking in tongues. (Acts 2:1, 8: 12-17, 10:44-48, etc.) Paul is used to heal Jews, Gentiles, etc. by laying hands on the sick. (Acts 14:10, 19:11-12, 20:10-12, 28:8) Paul is unharmed after being bitten by a serpent. (Acts 28:5) And, demons are cast out. (Acts 16:18)
Jesus does not lie and He said: "
Truly, truly, I tell you, WHOEVER
believes in Me will also do the works that I am doing. He will do even greater things than these, because I am going to the Father. 13And I will do whatever you ask in My name, so that the Father may be glorified in the Son..." John 14:12-13
I repeat, signs and wonders are done to authenticate the Gospel of the Kingdom.
The Jewish leaders repeatedly reject the Holy Spirit, who was the member of the Trinity responsible for these signs and wonders in Acts.
Acts 4 The priests and the captain of the temple guard and the Sadducees came up to Peter and John while they were speaking to the people. 2 They were greatly disturbed because the apostles were teaching the people, proclaiming in Jesus the resurrection of the dead.
8 Then
Peter, filled with the Holy Spirit, said to them: “Rulers and elders of the people! 9 If we are being called to account today for an act of kindness shown to a man who was lame and are being asked how he was healed, 10 then know this, you and all the people of Israel: It is by the name of Jesus Christ of Nazareth, whom you crucified but whom God raised from the dead, that this man stands before you healed.
16 “What are we going to do with these men?” they asked.
“Everyone living in Jerusalem knows they have performed a notable sign, and we cannot deny it. 17 But to stop this thing from spreading any further among the people, we must warn them to speak no longer to anyone in this name.”
Peter witnessed for himself how, despite the Holy Spirit giving them signs and wonders to verify their message to the Jewish nation, the leaders are determined to reject God. Peter also knew what happened to Stephen in Acts 6 and 7
8 Now
Stephen, a man full of God’s grace and power, performed great wonders and signs among the people. 9 Opposition arose, however, from members of the Synagogue of the Freedmen (as it was called)—Jews of Cyrene and Alexandria as well as the provinces of Cilicia and Asia—who began to argue with Stephen. 10 But they could not stand up against the wisdom the Spirit gave him as he spoke.
15 All who were sitting in the Sanhedrin looked intently at Stephen, and they saw that his face was like the face of an angel.
Acts 7
54 When the members of the Sanhedrin heard this, they were furious and gnashed their teeth at him. 55
But Stephen, full of the Holy Spirit, looked up to heaven and saw the glory of God, and Jesus standing at the right hand of God. 56 “Look,” he said, “I see heaven open and the Son of Man standing at the right hand of God.”
57
At this they covered their ears and, yelling at the top of their voices, they all rushed at him, 58 dragged him out of the city and began to stone him. Meanwhile, the witnesses laid their coats at the feet of a young man named Saul.
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When Peter heard of this account, I strongly suspect he sensed that the Jewish nation is determined to reject what the Holy Spirit is doing in Israel through them. The Great Commission that Jesus gave them in Matthew 28 was not going to be fulfilled, the Jewish leaders are committing the blasphemy of the Holy Spirit by rejecting their message, which under the Law of Moses, was an unforgivable sin.
By the time Peter witnessed in Acts 10 that God is granting the Gentiles the Holy Spirit, indicating that God is now saving Gentiles without them having to do what Peter believed must be done in Acts 2:38, that is to repent and be baptized, Peter could sense that God is phasing out the Kingdom gospel to usher in a new program, which we now know as the Gospel of Grace.