Acts 13:51

‘But they shook off the dust of their feet against them, and came to Iconium.'

But this did not put Paul and Barnabas out. They shook the dust off their feet, both revealing that their task was done in that region and they were moving on, and as a testimony against those who had turned them away. This was in accordance with the teaching of Jesus Himself. The dust would stand as a testimony to God in that Day, both of the fact that the Kingly Rule of God had been brought to them, and that they had chosen to turn from it (Luke 10:10), and of the treatment they had meted out to His servants. Now they could begin again in Iconium.