Albert Barnes Commentary Acts 2:5

"Now there were dwelling at Jerusalem Jews, devout men, from every nation under heaven." — Acts 2:5 (ASV)

There were dwelling at Jerusalem. The word rendered katoikountes properly means to have a fixed and permanent habitation, in distinction from another word, paroikountes, which means to have a temporary and transient residence in a place. But it is not always confined to this signification; and it is not improbable that many wealthy foreign Jews had a permanent residence in Jerusalem for the convenience of being near the temple. This was the more probable, as about that time the Messiah was expected to appear (Matthew 2).

Jews. Jews by birth; of Jewish descent and religion.

Devout men. Andres eulabeis. Literally, men of cautious and circumspect lives, who lived in a prudent manner. The term is applied to men who were cautious about offending God and who were careful to observe His commandments. Thus, it is a general expression to denote pious or religious men. Acts 8:2 says, And devout men carried Stephen to his burial.Luke 2:25 states, And the same man (Simeon) was just and devout. The word devout means "yielding a solemn and reverential attention to God in religious exercises, particularly in prayer; pious, sincere, solemn" (Webster), and very well expresses the force of the original.

Out of every nation under heaven. This is a general expression, meaning from all parts of the earth. The countries from which they came are more particularly specified in Acts 2:9-11. The Jews at that time were scattered into almost all nations, and in all places had synagogues. (See Barnes on John 7:35).

Still, they would naturally desire to be present as often as possible at the great feasts of the nation in Jerusalem. Many would seek a residence there for the convenience of being present at the religious solemnities. Many who came up to the Feast of Passover would remain for the Feast of Pentecost. Consequently, on such occasions, the city would be full of strangers.

We are told that when Titus besieged Jerusalem around the time of the Feast of Passover, there were no fewer than three million people in the city, and this great multitude greatly deepened the calamities arising from the siege. Josephus also mentions an instance where great multitudes of Jews from other nations were present at the Feast of Pentecost (Jewish Wars, Book 2, Chapter 3, Section 1).