Acts 11 repeats and continues Trinitarian themes already seen in the book. In Acts 11:15-18, Peter recounts the events of Acts chapter 10 and the spread of the gospel to the Gentiles:
As I began to speak, the Holy Spirit fell on them just as on us at the beginning. And I remembered the word of the Lord, how he said, ‘John baptized with water, but you will be baptized with the Holy Spirit.’ If then God gave the same gift to them as he gave to us when we believed in the Lord Jesus Christ, who was I that I could stand in God‘s way?” When they heard these things they fell silent. And they glorified God, saying, “Then to the Gentiles also God has granted repentance that leads to life.”
In giving his apologia in Jerusalem, Peter maintains the Trinitarian emphasis seen in Acts 10:38. The spread of the gospel to the Gentiles is the work of the Trinity and must be embraced as such by God’s people. We also see repeated the truth that the Holy Spirit is given as the gift of God.
Beginning in Acts 11:19 Luke backtracks in the narrative a somewhat and returns to the scattering that resulted from Saul and the Sanhedrin’s persecution of Stephen. Most of the believers sought to spread the gospel among Jews and the Jews alone (11:19); but some of the believers crossed the religious-ethnic boundary and proclaimed the Lord to Hellenists, or Greeks, as well. The Trinity blessed this effort:
But there were some of them, men of Cyprus and Cyrene, who on coming to Antioch spoke to the Hellenists also, preaching the Lord Jesus. And the hand of the Lord was with them, and a great number who believed turned to the Lord. The report of this came to the ears of the church in Jerusalem, and they sent Barnabas to Antioch. When he came and saw the grace of God, he was glad, and he exhorted them all to remain faithful to the Lord with steadfast purpose, for he was a good man, full of the Holy Spirit and of faith. And a great many people were added to the Lord. Acts 11:20-24
Once again the Trinity is seen as actively involved in the spread of the gospel. The Trinity is inherently missionary.