The morning after that Sabbath therefore was, according to our reckoning, Sunday morning. In that year it was the morning on which the Lord rose, or the first day of the week.
From it seven full weeks, or fifty days, had to be counted. On the fiftieth day they were to keep the feast to Jehovah God.
Thus the feast of the Jewish Pentecost in that year fell on the first day of the week, or Sunday by our reckoning. It was the fiftieth day after the resurrection of Christ.
This Jewish feast, the feast of weeks (Tob 2:1; 2 Macc 12:23), or the feast of the first fruits (Ex 23:16; Num 28:26), was established for the sanctification of the harvest or first fruits.
It was one of the three great feasts at which every male, except children and the infirm, had to celebrate in Jerusalem. These were Pascha, Pentecost, and Tabernacles (Ex 23:14-16; Deut 16:16). It was celebrated joyfully and brightly (Deut 16:11).
With this feast there was also joined the commemoration of the giving of the law on Sinai. This was because, on the third day of the third month after the Hebrews came out of Egypt, the Lord descended upon Sinai to give the law (Ex 19:1, 10-11).
The Hebrews had come out of Egypt on the night of Pascha (Ex 13:3 and parallels). Consequently, the day of the giving of the law was the fiftieth day after the Pascha of the exodus; cf. Theophylact.
This important Jewish feast, the feast of new fruits and of the Sinaitic lawgiving, was the greatest day for the first Christian community. It was the day of the descent of the Holy Spirit.
It was the day when the first spiritual fruits were offered to the Lord in the persons of the three thousand baptized that day (v. 41). It was the day of a new lawgiving, replacing the ancient one.
“On the day on which the law was given, the grace of the Spirit also had to be bestowed. For as the Savior, when He was about to endure His holy Passion, was pleased to surrender Himself to that Passion at no other time than when the lamb was slain. So as to unite the truth with the type itself, so also the descent of the Holy Spirit, by the good pleasure from above, was granted at no other time than when the law was given.
This showed that both then and now it is the Holy Spirit who gives the law. Since on the day of Pentecost the sheaves of the new fruits were brought, and various persons came together under one heaven in Jerusalem, on this same day the first fruits from every nation, from all nations dwelling under heaven, were to be gathered into one sheaf of piety and brought to God, according to the apostolic word” (Theophylact; cf. in part Chrysostom).
“Were all with one accord together”: who were these all, and where were they? The word “all,” to which “they” is added in the Russian translation, and “the apostles” in the Slavonic, seems unable to be limited to the twelve apostles alone.
Rather, it must mean all the believers in Christ who were then in Jerusalem. At one of the preceding gatherings there had been about one hundred and twenty (Acts 1:16), and now perhaps there were even more.
The emphatic word “all” (ἄπαντες), used as though deliberately and intentionally, does not suit the small band of only twelve apostles. This is especially so since the preceding narrative spoke of a much greater number of Christ's disciples.
Further on, moreover, the twelve apostles are rather clearly distinguished from others who were present in this gathering (v. 14). The application by the Apostle Peter, in his following speech, of Joel's prophecy to the event also indicates a large number of persons gathered (v. 16 ff.).
It is entirely natural to suppose that, on such a great feast near the hour of prayer (v. 15), all the believers were together with the apostles. They were probably even more numerous than at the preceding gathering.
Then the believers were probably only those of Jerusalem; cf. the note on Acts 1:16. Now, for the feast, believers had surely come from Judea, Galilee, beyond the Jordan, and the neighboring regions.
They undoubtedly used this occasion to be together with the apostles and the other believers in Christ from Jerusalem.
Where were they gathered together at this time? There is no direct indication. From the following words of the narrative (v. 2), it is only clear that the gathering was in a house.
Perhaps it was in the same house in which the preceding gathering had also taken place (Acts 1:15 ff.). It is difficult to suppose that this was in one of the temple annexes.
Josephus does call them ὀίκιες, “houses” (Antt. 8.3.2). Yet they were under the supervision of the Sanhedrin, which had shown such hostility toward Christ and His disciples, and of which the Lord's disciples had recently been afraid (Jn 20:19).
It is most likely to suppose that this was the house of a private person, a disciple of the Lord. Was it not again that large upper room where the mystery of the Eucharist was first celebrated?
After that celebration the Lord promised to send the disciples another Comforter. Did this Comforter come to them in that same place?