A.T. Robertson Commentary Acts 16:13

"And on the sabbath day we went forth without the gate by a river side, where we supposed there was a place of prayer; and we sat down, and spake unto the women that were come together." — Acts 16:13 (ASV)

By a river side (παρα ποταμον). The little river Gangites (or Gargites) was one mile west of the town. Philippi as a military outpost had few Jews. There was evidently no synagogue inside the city, but "without the gates" (εξω της πυλης) they had noticed an enclosure "where we supposed" (ου ενομιζομεν, correct text, imperfect active), probably as they came into the city, "was a place of prayer" (προσχυχην εινα). Infinitive with accusative of general reference in indirect discourse. Προσευχη is common in the LXX and the N.T. for the act of prayer as in Ac 2:42 then for a place of prayer either a synagogue (III Macc. 7:20) or more often an open air enclosure near the sea or a river where there was water for ceremonial ablutions. The word occurs also in heathen writers for a place of prayer (Schurer, Jewish People, Div. II, Vol. II, p. 69, Engl. Tr.). Deissmann (Bible Studies, p. 222) quotes an Egyptian inscription of the third century B.C. with this sense of the word and one from Panticapaeum on the Black Sea of the first century A.D. (Light from the Ancient East, p. 102). Juvenal (III. 296) has a sneering reference to the Jewish προσευχα. Josephus (Ant. XIV. 10, 23) quotes a decree of Halicarnassus which allowed the Jews "to make their prayers (προσευχας) on the seashore according to the custom of their fathers." There was a synagogue in Thessalonica, but apparently none in Amphipolis and Apollonia (Acts 17:1). The rule of the rabbis required ten men to constitute a synagogue, but here were gathered only a group of women at the hour of prayer. In pioneer days in this country it was a common thing to preach under bush arbours in the open air. John Wesley and George Whitfield were great open air preachers. Paul did not have an inspiring beginning for his work in Europe, but he took hold where he could. The conjecture was correct. It was a place of prayer, but only a bunch of women had come together (ταις συνελθουσαις γυναιξιν), excuse enough for not preaching to some preachers, but not to Paul and his party. The "man of Macedonia" turned out to be a group of women (Furneaux). Macedonian inscriptions show greater freedom for women in Macedonia than elsewhere at this time and confirm Luke's story of the activities of women in Philippi, Thessalonica, Berea.

We sat down and spake (καθισαντες ελαλουμεν). Having taken our seats (aorist active participle of καθιζω) we began to speak or preach (inchoative imperfect of λαλεω, often used for preaching). Sitting was the Jewish attitude for public speaking. It was not mere conversation, but more likely conversational preaching of an historical and expository character. Luke's use of the first person plural implies that each of the four (Paul, Silas, Timothy, Luke) preached in turn, with Paul as chief speaker.