Paul the Apostle, originally known as Saul, had first persecuted Christians. He (Saul/Paul) was there at the stoning of Stephen. Afterwards, Saul (Paul) had a sovereign experience with Jesus and was converted. At first Paul preached to the Jews. However, certain Jews rejected him (and Barnabus who was ministering with Paul) and it is here that he declares that he will begin to preach to the Gentiles who were the non-Jewish people of the day.
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Acts 13:45 But when the Jews saw the multitudes, they were filled with envy, and spake against those things which were spoken by Paul, contradicting and blaspheming.
46 Then Paul and Barnabas waxed bold, and said, It was necessary that the word of God should first have been spoken to you: but seeing ye put it from you, and judge yourselves unworthy of everlasting life, lo, we turn to the Gentiles.
47 For so hath the Lord commanded us, saying, I have set thee to be a light of the Gentiles, that thou shouldest be for salvation unto the ends of the earth.
48 And when the Gentiles heard this, they were glad, and glorified the word of the Lord: and as many as were ordained to eternal life believed.
49 And the word of the Lord was published throughout all the region.
50 But the Jews stirred up the devout and honourable women, and the chief men of the city, and raised persecution against Paul and Barnabas, and expelled them out of their coasts.
51 But they shook off the dust of their feet against them, and came unto Iconium.
52 And the disciples were filled with joy, and with the Holy Ghost.
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