The Sabbath day referred to is evidently the first Sabbath day after their arrival in the city. Out of the city is literally “out of the gate” but the gate referred to is the “city gate” (New English Bible, Jerusalem Bible). The river mentioned is the Gangites (or Angites).

Place for prayer (see Jerusalem Bible, Moffatt, Barclay) translates a word which generally means merely “prayer,” but here and in verse 16 it means “place for prayer,” a meaning which is also attested outside the New Testament. It is better to translate this term in the generalized sense of “a place for prayer” rather than with a specific meaning of “synagogue,” since Luke did use the word synagogue elsewhere and could have used it here had he so desired.

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on The Acts of the Apostles. (UBS Handbook Series). New York: UBS, 1972. For this and other handbooks for translators see here .