Acts 2:5 - Coke's Commentary on the Holy Bible

There were dwelling at Jerusalem Jews, &c.— There were sojourning, &c. κατοικουντες. Devout or pious men, is a title applied not only to those religious persons who observed the Jewish law, but likewise to those Heathens who had renounced idolatry, and lived a life of piety and holiness. From every nation under heavencan signify no more than "from all the several nations among whom the Jews were dispersed." The Jews were then so numerous, as to have spread through every country; so that, as Agrippa, in Josephus, says, "there was not a people upon earth who had not Jews inhabiting among them." These men were come up to Jerusalem, not only upon account of the festival then celebrating, but in expectation of the Messiah, who was to be manifested about that time accordingto the concurring testimony of the prophets.