What is the meaning of Acts 28:11-15?

11 And after three months we departed in a ship of Alexandria, which had wintered in the isle, whose sign was Castor and Pollux. 12 And landing at Syracuse, we tarried there three days. 13 And from thence we fetched a compass, and came to Rhegium: and after one day the south wind blew, and we came the next day to Puteoli: 14 Where we found brethren, and were desired to tarry with them seven days: and so we went toward Rome. 15 And from thence, when the brethren heard of us, they came to meet us as far as Appii forum, and The three taverns: whom when Paul saw, he thanked God, and took courage. (Acts 28:11-15 KJV)

William Burkitt’s Commentary

Observe here, 1. That Apostle Paul at the command of God, though shipwrecked before, yet puts forth to sea again. A clear call from God will carry on a Christian cheerfully to grapple with all imaginary difficulties and dangers, without either dispute or delay.

Thus did the apostle here; he enters a ship of Alexandria, sails from Malta to Syracuse in Sicily, from thence to Rhegium in Italy, and from thence to Puteoli; where they found some Christians, with whom they abode seven days.

Here note, How wonderfully the Christian religion was spread abroad in the Italian country, yea, in and about Rome before St. Paul’s coming thither. From Puteoli the apostle passes to Rome, the chief city in Italy, the empress of the world and the seat of the Roman emperor. He is met upon the road by many eminent persons, as conquerors used to be, to congratulate their great victories; even by Christians, who are called brethren,  Ac 28:15, who are not ashamed of St. Paul’s chain, but left their houses and came forth to meet him, some fifty miles, others thirty; someone day’s journey, others two; to congratulate his coming, and pay their respect to him: for which favour the apostle thanked God and took courage. That is, he owned it as an encouragement sent from God to him and was greatly refreshed by their company. But how came Christians so early to be found in Rome? Who converted them? St. Paul had never been there till now, and we read not of St. Peter, or any of the apostles, having been there thus early; yet St. Paul finds many Christians at and about Rome.

Answer. These brethren are thought to be converted by such as were present at Jerusalem at the feast of Pentecost, Ac 2:10, where it is expressly said, That there were strangers of Rome then present when those mighty miracles were done there; and we may suppose that they, becoming true converts at that time, did propagate the gospel in and about Rome, according to their ability; and the blessing of God so accompanied and succeeded their endeavours that the apostle now found some saints even in Nero’s house:  Thus mightily grew the word of God, and prevailed.