When Paul arrived in Rome, he first preached to the Jews living there. This was in line with his usual practice of preaching to the Jews first before turning to the Gentiles.

Biblical Reference (Acts 28:17, RSV):

"After three days he called together the local leaders of the Jews; and when they had gathered, he said to them, ‘Brethren, though I had done nothing against the people or the customs of our fathers, yet I was delivered as a prisoner from Jerusalem into the hands of the Romans.’”

Paul explained his situation to them and later preached about Jesus Christ, but some of the Jews rejected his message. As a result, Paul then turned to the Gentiles (Acts 28:28).