Being sent forth by the Holy Ghost - Having been called to this world by the Holy Spirit, and being under his direction.
Departed unto Seleucia - This city was situated at the mouth of the river Orontes, where it fails into the Mediterranean. Antioch was connected with the sea by the Orontes River. Strabo says that in his time they sailed up the river in one day. The distance from Antioch to Seleucia by water is about 41 miles, while the journey by land is only 16 12 miles (Life and Epistles of Paul, vol. 1, p. 185. “Seleucia united the two characters of a fortress and a seaport. It was situated on a rocky eminence, which is the southern extremity of an elevated range of hills projecting from Mount Aranus. From the southeast, where the ruins of the Antioch gate are still conspicuous, the ground rose toward the northeast into high and craggy summits; and round the greater part of the circumference of 4 miles the city was protected by its natural position. The harbor and mercantile suburb were on level ground toward the west; but here, as on the only weak point at Gibraltar, strong artificial defenses had made compensation for the weakness of nature. Seleucus, who had named his metropolis in his father’s honor (p. 122), gave his own name to this maritime fortress; and here, around his tomb, his successors contended for the key of Syria. ‘Seleucia by the sea’ was a place of great importance under the Seleucidae and the Ptolemies, and so it remained under the sway of the Romans. In consequence of its bold resistance to Tigranes when he was in possession of all the neighboring country, Pompey gave it the privileges of a ‘free city;’ and a contemporary of Paul speaks of it as having those privileges still.
Here, in the midst of unsympathizing sailors, the two missionary apostles, with their younger companion, stepped on board the vessel which was to convey them to Salamis. As they cleared the port, the whole sweep of the bay of Antioch opened on their left - the low ground by the mouth of the Orontes; the wild and woody country beyond it; and then the peak of Mount Casius, rising symmetrically from the very edge of the sea to a height of 5000 feet. On the right, in the southwest horizon, if the day was clear, they saw the island of Cyprus from the first. The current sets northerly and northeast between the island and the Syrian coast. But with a fair wind, a few hours would enable them to run down from Seleucia to Salamis, and the land would rapidly rise in forms well known and familiar to Barnabas and Mark” (Life and Epistles of Paul, vol. 1, pp. 135, 138).
They sailed to Cyprus - An island in the Mediterranean, not far from Seleucia. See the notes on Acts 4:36.