15 After the reading from the Law and the Prophets, the leaders of the synagogue sent word to them, saying, “Brothers, if you have a word of exhortation for the people, please speak.”

Read Acts 13:15 Using Other Translations

And after the reading of the law and the prophets the rulers of the synagogue sent unto them, saying, Ye men and brethren, if ye have any word of exhortation for the people, say on.
After the reading from the Law and the Prophets, the rulers of the synagogue sent a message to them, saying, "Brothers, if you have any word of encouragement for the people, say it."
After the usual readings from the books of Moses and the prophets, those in charge of the service sent them this message: “Brothers, if you have any word of encouragement for the people, come and give it.”