In journeyings often, in perils of waters, in perils of robbers, in perils by mine own countrymen, in perils by the heathen, in perils in the city, in perils in the wilderness, in perils in the sea, in perils among false brethren;
In - rather 'By:' connected with 2 Corinthians 11:23, but now not with "in," as there, and as in 2 Corinthians 11:27, where again he passes to the idea of surrounding circumstances or environments (Alford).
Waters, х potamon (G4215)] - 'rivers'; namely, perils by their flooding, as on the road often traversed by Paul between Jerusalem and Antioch, crossed by the torrents rushing down from Lebanon.
Robbers - perhaps in his journey from Perga to Antioch in Pisidia. Pisidia was notorious for robbers; as indeed were all the mountains that divided the high land of Asia from the sea.
The heathen - Gentiles.
In the city - Damascus (Acts 9:24-25), Jerusalem (Acts 9:29), Ephesus (Acts 19:23).
False brethren (Galatians 2:4).