It was most assuredly not sunday, but saturday night, which is biblically the first day of the week, and the only time that any disciple of Yeshua met on the first day of the week!
How can you insist that? It is has been shown you multiple times when they did, as the eleven disciples on the evening of the Resurrection (Mark 16:14-18; Luke 24:36-44; John 20:19-23) and Eight days later (John 20:26-29) and on Pentecost (cf. Leviticus 23:15) And 1Cor. 16:2 indicates a meeting, nor just a gathering of money with no meeting.
And Acts 20:7 does not say on "upon the last day of the week" that "Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight," but upon the first day of the week, Sat. evening, after the Sabbath ended.
If it says on the first day of the week in Gods word, it was saturday night by pagan measure.
Exactly, and the 1st day began then!
Havdalah, on saturday night, was a part of the closing of their day of worship, and often lasted into the wee hours if Paul was present.
You are simply admitting what you denied, that the disciples met on the 1st day of the week, as Scripture says, which was Sat night.
The fact is that the Holy Spirit choose to use the "first" of the week and not on the Sabbath that they had their meeting, and . nowhere shows the NT church specifically having their meeting on the 7th day, as He does on the 1st, nor reiterates or repeats the 4th commandment while the rest are, and the only teaching under the new cov. regarding Christian observance of the 7th day is that which makes it part of the ceremonial laws, and a shadow of the rest that believers are given in Christ.
If you cannot see warrant for our position then goodbye.
The point was not the first day, but the closing of their worship day, the Sabbath, that was the center of their activities. Every mention of the first day in the NT is of this nature. The first day never had any significance to them of its own.