As Peter returned to Jerusalem from Cornelius’s house, he began to face criticism. He had gone into the house of a Gentile, and had even eaten with them. That is definitely unlawful, according to the Jewish customs.
But Peter had a story that they hadn’t heard. They thought they knew all that they needed to know, but in truth, God was doing something different. He was doing something new. Peter told them of his vision and about the angel that had appeared to Cornelius. He told them of the other witnesses that had gone with him to Cornelius’s house. He told them that the Holy Spirit had told him not to fear going with the men that Cornelius had sent to find him.
But the closer to the conversation was that Peter told them that they had received the Holy Spirit. As he was preaching, the Holy Spirit came upon all of the people in Cornelius’s house, and this is a definite confirmation that God has accepted these people. Even the Gentiles, whom had never been God’s people, were now accepted into God’s family. Even they are now saved and given eternal life.
When they heard this, they had no further objections and praised God, saying, “So then, even to Gentiles God has granted repentance that leads to life.”
Acts 11:18
The Holy Spirit is the confirmation. Someone might be able to be baptized, but only the Spirit of God can confirm the work that God has done in that person’s life. If the person has received the Holy Spirit, that person has now been made to be a new creation and is fully and wholly accepted by God. Otherwise, they are not. Otherwise, they haven’t entered into God’s grace and mercy.
Peter said that he remembered what Jesus had told them: John baptized with water, but you will be baptized with the Holy Spirit. Man will baptize with water, but God will give His Holy Spirit. Jesus himself is the one who will give his Spirit to his people.