I know this wasn't directed toward me, but I would still like to comment on it. If you are implying that we should worship on the day on which the church was created and infilled, then I'd like to point out that it was on the feast of Weeks, which is one of the feasts listed in Leviticus 23. If we are to be worshiping on one of the feasts, it is only logical to assume that we should also worship on the others, one of which is the weekly Sabbath.
The TOG
Here is the background from the ISBE (International Standard Bible Encyclopedia):
In the Old Testament:
As the name indicates (pentekoste), this second of the great Jewish national festivals was observed on the 50th day, or 7 weeks, from the Paschal Feast, and therefore in the Old Testament it was called "the feast of weeks." It is but once mentioned in the historical books of the Old Testament (2Ch 8:12,13), from which reference it is plain, however, that the people of Israel, in Solomon's day, were perfectly familiar with it: "offering according to the commandment of Moses, on the sabbaths, and on the new moons, and on the set feasts, three times in the year, even in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles." The requirements of the three great festivals were then well understood at this time, and their authority was founded in the Mosaic Law and unquestioned. The festival and its ritual were minutely described in this Law. Every male in Israel was on that day required to appear before the Lord at the sanctuary (Ex 34:22,23).
Correctly, you point out that it was on that day that Holy Spirit infilled the church. Yet you seem to miss what I made blue in the snip. From the beginning, this, the second of the great feasts is required to be on the FIRST day of the week, the day we call Sunday. That is because the Paschal Feast was always on the last Sabbath of the "Passover Season" which always begins at sundown on Nisan 14. Since there are obviously 7 days in a week, and there are seven weeks plus one day when the Pentecost is celebrated, 49 + 1 = 50, and that is how the name of the Feast became Hellenized to "Pentecost" because "Pentecost" is the name for 50 in Greek.
In the later Rabbinical writings, the Rabbis also declared that the day of Pentecost was the day that Moses brought the Torah (Law) to the Jews. What I am stating here is that Pentecost was a very important religious feast in the life of Judaism, and most significant is this sentence: "
Every male in Israel was on that day required to appear before the Lord at the sanctuary (Ex 34:22,23)." What they did on that FIRST day in the sanctuary was to worship. EVERY MALE in Israel was REQUIRED to go to the sanctuary and worship on the day we call Sunday, the FIRST day of the week.
There should be no disagreement on that so far because I backed up everything with Scripture references..
More ISBE:
The old rendering of sumplerousthai (Ac 2:1) by "was fully come" was taken by Lightfoot (Her. Heb.) to signify that the Christian Pentecost did not coincide with the Jewish, just as Christ's last meal with His disciples was considered not to have coincided with the Jewish Passover, on Nisan 14. The bearing of the one on the other is obvious; they stand and fall together
In other words, they did not fall this way by happenstance; there was obviously a plan of God FROM THE BEGINNING to link them together so that is is "mandatory" to see that the two feasts are linked together, and cannot be separated without doing violence to the Word of God.
More ISBE:
The Holy Spirit descended in answer to the explicit promise of the glorified Lord, and the disciples had been prayerfully waiting for its fulfillment (Ac 1:4,14). The Spirit came upon them as "a power from on high." God the Holy Spirit proved on Pentecost His personal existence, and the intellects, the hearts, the lives of the apostles were on that day miraculously changed. By that day they were fitted for the arduous work that lay before them. There is some difference of opinion as to what is the significance of Pentecost for the church as an institution. The almost universal opinion among theologians and exegetes is this: that Pentecost marks the rounding of the Christian church as an institution. This day is said to mark the dividing line between the ministry of the Lord and the ministry of the Spirit.
So Pentecost is sort of like a "Theological Mason-Dixon Line" in that it marked the end of the visible presence of Jesus Christ because His Ascension was 40 days after the (most likely on a Friday, if I count correctly) Paschal Feast, and 10 days afterward, the Feast of Weeks came on a Sunday, the first day of the week.
You stated, "If we are to be worshiping on one of the feasts... " I never suggested that. What I am saying is that to dismiss the obvious connection between the Paschal Feast (Seder) and Pentecost is to relegate to mere circumstance that the two feasts fall as they do. I do not believe that is warranted. I am also pointing to the fact that from the beginning, Pentecost was created to happen after going to the Sanctuary and worshiping (by implication of the activities of the sanctuary) and the fact that they sat around a table and enjoyed the feast together. Therefore both worshiping in the Sanctuary and the celebrating of a feast are melded together so closely so that to disregard one part of the Passover-Pentecost relationship is to do irreparable damage to both.
Of course you can worship on ANY day of the week! However to create the artificial distinction that Sabbatarian churches do, and say, "Worship is supposed to be done on the day we call Saturday, the Sabbath." is to create a "law" for which there is no support. I can say that because to the best of my knowledge, there is no Scripture in the OT that links Sabbath, a day of REST with the day for worship, proscribed to be so since its beginning (Ex 34:22,23).
That is why I say as I do on the issue.