Why did Paul go to a riverside park in Philippi on the Sabbath?
Paul went to the riverside park in Philippi on the Sabbath because Jewish people were meeting there. Evidently they had no synagogue, so they gathered by the river. He went to that place where they worshiped God, and there he spoke to them.
Les explains that Paul had recently come to Philippi after the Macedonian call. On that particular Sabbath, Paul went out to a little riverside park where Jewish people were evidently meeting, since they did not have a synagogue. Les notes that at that gathering, Lydia, a seller of purple from Thyatira who worshiped God but knew nothing of God's salvation, heard Paul. Les emphasizes that the Lord opened her heart, not Paul's preaching, and when she opened her heart she attended to the things spoken by Paul. Les connects this to the principle that God makes the first move, as also seen with Cornelius and the Ethiopian eunuch.