2:5 There were dwelling at Jerusalem Jews, devout men. Devout Jews who had come up to the great feast of Pentecost. The Jews were already scattered in many nations, but foreign Jews were wont to flock to the great national feasts. Some, too, had come to end their days at Jerusalem.
Every nation under heaven. From all quarters of the world. Jews, in foreign lands, attended Pentecost in larger numbers than the other feasts, because the time of year favored travel.
2:5 And there were dwelling in Jerusalem Jews - Gathered from all parts by the peculiar providence of God.
2:5-13 The difference in languages which arose at Babel, has much hindered the spread of knowledge and religion. The instruments whom the Lord first employed in spreading the Christian religion, could have made no progress without this gift, which proved that their authority was from God.