The next Sabbath almost the whole city gathered to hear the word of the Lord. But when the Jews saw the crowds, they were filled with jealousy and began to contradict what was spoken by Paul, reviling him. And Paul and Barnabas spoke out boldly, saying, “It was necessary that the word of God be spoken first to you (the Jews). Since you thrust it aside and judge yourselves unworthy of eternal life, behold, we are turning to the Gentiles. For so the Lord has commanded us, saying, “‘I have made you a light for the Gentiles, that you may bring salvation to the ends of the earth.'” And when the Gentiles heard this, they began rejoicing and glorifying the word of the Lord, and as many as were appointed to eternal life believed. – Acts 13:44-48 (ESV)

13:44-45. On the next Sabbath . . . the Jews (i.e., Jewish leaders), moved by jealousy . . . talked abusively against what Paul was saying (“abusively” renders the Gr. participle blasphēmountes).

13:46. To combat this Jewish opposition Paul and Barnabas answered them boldly, We had to speak the Word of God to you first. Apostolic preaching was noted for its boldness.

It was necessary that the apostles go to the Jews first for a number of reasons. First, the coming of the earthly kingdom depended on Israel’s response to the coming of Christ (cf. Matt. 23:39; Rom. 11:26). Second, only after Israel rejected the gospel could Paul devote himself to the Gentiles. Third, the message of Jesus is fundamentally Jewish in that the Old Testament, the Messiah, and the promises are all Jewish. (On “the Jew first,” cf. Acts 3:26; Rom. 1:16.)

So Paul turned to the Gentiles in Antioch. This pattern was repeated in city after city until Paul reached Rome (cf. Acts 13:50-51; 14:2-6; 17:5, 13-15; 18:6; 19:8-9). There for the final time in the book the Apostle Paul turned from Jews to Gentiles (28:23-28).

13:47. In thus turning to the Gentiles Paul and Barnabas saw an outworking of the prophecy of Isaiah 49:6, I have made you a light to the Gentiles. This Old Testament passage has at least three applications—to Israel (Isa. 49:3), to Christ (Luke 2:29-32), and to Paul, the apostle to the Gentiles.

13:48. The Gentiles rejoiced in this turn of events and all who were appointed for eternal life believed. It is difficult to miss the doctrine of God’s election here; the words “were appointed” come from the verb tassō, a military word meaning “to arrange” or “to assign.” Luke used it here to show that God’s elective decree included Gentiles.

cf., confer, compare

Walvoord, John F. ; Zuck, Roy B. ; Dallas Theological Seminary: The Bible Knowledge Commentary : An Exposition of the Scriptures. Wheaton, IL : Victor Books, 1983-c1985, S. 2:390