A.T. Robertson Commentary Acts 2:5

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

Were dwelling (ησαν κατοικουντες). Periphrastic imperfect active indicative. Usually κατοικεω means residence in a place (4:16; 7:24; 9:22,32) as in verse 14 (Luke 13:4). Perhaps some had come to Jerusalem to live while others were here only temporarily, for the same word occurs in verse 9 of those who dwell in Mesopotamia, etc.

Devout (ευλαβεις). Reverent (ευ, well, λαμβανω, to take). See on Lu 2:25 like Simeon waiting for the consolation of Israel or hoping to die and be buried in the Holy City and also Ac 8:2.