Amphipolis - This was the capital of the eastern province of Macedonia. It was originally a colony of the Athenians, but under the Romans it was made the capital of that part of Macedonia. It was near to Thrace, and was situated not far from the mouth of the river Strymon, which flowed around the city, and thus occasioned its name, around the city. The distances laid down in the Itineraries in regard to these places are as follows: Philippi to Amphipolis, 33 miles; Amphipolis to Apollonia, 30 miles; Apollonia to Thessalonica, 37 miles. “These distances are evidently such as might have been traversed each in one day; and since nothing is said of any delay on the road, but everything to imply that the journey was rapid, we conclude (unless, indeed, their recent sufferings made rapid traveling impossible) that Paul and Silas rested one night at each of the intermediate places, and thus our notice of their journey is divided into three parts. The position of Amphipolis is one of the most important in Greece. It stands in a pass which Traverses the mountains bordering the Strymonic Gulf, and it commands the only easy communication from the coast of that gulf into the great Macedonian plains, which extend, for 60 miles, from beyond Meleniko to Philippi. The ancient name of the place was ‘Nine Ways,’ from the great number of Thracian and Macedonian roads which met at this point. The Athenians saw the importance of the position, and established a colony there, which they called Amphipolis, because the river surrounded it.
And Apollonia - This city was situated between Amphipolis and Thessalonica, and was formerly much celebrated for its trade.
They came to Thessalonica - This was a seaport of the second part of Macedonia. It is situated at the head of the Bay Thermaicus. It was made the capital of the second division of Macedonia by Aemilius Paulus, when he divided the country into four districts. It was formerly called Therma, but afterward received the name of Thessalonica, either from Cassander, in honor of his wife Thessalonica, the daughter of Philip, or in honor of a victory which Philip obtained over the armies of Thessaly. It was inhabited by Greeks, Romans, and Jews. It is now called Saloniki, and, from its situation, must always be a place of commercial importance. It is situated on the inner bend of the Thermaic Gulf, halfway between the Adriatic and the Hellespont, on the sea margin of a vast plain, watered by several rivers, and was evidently designed for a commercial emporium. It has a population at present of 60,000 or 70,000, about half of whom are Jews. They are said to have 36 synagogues, “none of them remarkable for their neatness or elegance of style.” In this place a church was collected, to which Paul afterward addressed the two epistles to the Thessalonians.
Where was a synagogue - Greek: where was the synagogue (ἡ συναγωγὴ hē sunagōgē) of the Jews. It has been remarked by Grotius and Kuinoel that the article used here is emphatic, and denotes that there was probably no synagogue at Amphipolis and Apollonia. This was the reason why they passed through those places without making any delay.