Acts 13:4

Barnabas and Saul Sail for Cyprus And Minister There (13:4-12).

‘So they, being sent forth by the Holy Spirit, went down to Seleucia; and from there they sailed to Cyprus.'

What was most important was that it was essentially the Holy Spirit Who was sending them forth. He had set them apart and now He was sending them. Note the great emphasis on  the Spirit's actions in sending them. This was a continuation of the work of Pentecost. They carried with them Apostolic authority for Barnabas was the Apostles' appointed representative to Antioch, as well as walking in obedience to the Spirit. But Saul received his authority, partly because he was Barnabas' companion, and partly because he was chosen by the Spirit. Later he would declare that his Apostleship was not of men or by men, for he was here very conscious that the Holy Spirit was sending him, just as he had been very conscious that the Holy Spirit had revealed to him his doctrinal understanding from the Scriptures (Galatians 1:16 to Galatians 2:2).

We do not know whether they preached in the port of Seleucia, (16 miles west of Antioch), but their destination was Cyprus, an important island on the main shipping routes. This had been partly evangelised by those described in Acts 11:19, and it may have been their description of the interest shown even by God-fearers that was one cause of this journey. Furthermore, they may, conscious of how inadequate they had been in teaching the converts, have begged Barnabas and Saul to go there and confirm them in their faith and give them deeper understanding.