The message preached by the apostles required people to decide whether to trust in Jesus. Opinions were clearly divided.
Paul and Barnabas are called apostles for the first time (also in 14:14). This broadened the meaning of the word apostle. It no longer referred only to the Twelve. The Gospel of Luke shows an earlier example of this. Jesus sent out 70 (or 72) others as messengers (see Luke 10:1, 17).
Paul and Barnabas's message continued the work of the original apostles. They were ready to encounter difficulty and abuse for it, just as the earlier apostles had done (5:41; 14:19; 20:24; 21:13–14; see also Romans 8:35–38; 2 Corinthians 4:8–17).