Into the upper chamber (eis to huperōion). The upstairs or upper room (huper is upper or over, the adjective huperōios), the room upstairs where the women staid in Homer, then a room up under the flat roof for retirement or prayer (Act 9:37, Act 9:39), sometimes a large third story room suitable for gatherings (Act 20:9). It is possible, even probable, that this is the “large upper room” (anōgeon mega) of Mar 14:15; Luk 22:12. The Vulgate has coenaculum for both words. The word is used in the N.T. only in Acts. It was in a private house as in Luk 22:11 and not in the temple as Luk 24:53 might imply, “continually” (dia pantos) these words probably meaning on proper occasions.
They were abiding (ēsan katamenontes). Periphrastic imperfect active. Perfective use of kata, to abide permanently. It is possible that this is the house of Mary the mother of John Mark where the disciples later met for prayer (Act 12:12). Here alone in the N.T., though old compound. Some MSS. here read paramenontes. This could mean constant residence, but most likely frequent resort for prayer during these days, some being on hand all the time as they came and went.
Simon the Zealot (Simon ho Zēlōtēs). Called Simon the Cananaean (ho Cananaios) in Mat 10:4, Mar 3:18, but Zealot in Luk 6:16 as here giving the Greek equivalent of the Aramaic word because Luke has Gentiles in mind. The epithet (member of the party of Zealots) clung to him after he became an apostle and distinguishes him from Simon Peter. See note in Volume 1 on the Gospel of Matthew for discussion of the four lists of the apostles.
Judas the son of James (Joudas Iakōbou). Literally, Judas of James, whether son or brother (cf. Jud 1:1) we do not really know. “Of James” is added to distinguish him from Judas Iscariot (Joh 14:22). However we take it, he must be identified with the Thaddaeus (=Lebbaeus) of Mark and Matthew to make the list in the third group identical. No name appears in Acts for that of Judas Iscariot.