Acts 20:7, J.P. Green/Concordant Version
1Cor 16:2/Concordant Version
Luke 18:12/Concordant Version
Since you must be new to pre-Catholic history, I would point out that "Lord's Day" in Revelation 1:10 is a reference to the weekly Sabbath before paganism and anti-Semitism took over Christianity. Of course after this well known political change, propaganda was developed to de-judaize the NT documents.
Luke 18:12 means that they skipped two of the three meals on Sabbath. Jews are supposed to feast three meals, but some extra pious Jews skipped two in order to study and pray. Eliezer Segal of the U. of Calgary explains how some extra pious Jews fasted on Sabbath.
There is no evidence of a connection between the "first of the Sabbaths" and the rare Jewish counting of days to the Sabbath you reference. That's like saying that because monkeys and man share 98% DNA that they must be related.
There is no evidence of a connection between the "first of the Sabbaths" and the rare Jewish counting of days to the Sabbath you reference.You will have an uphill battle here attempting to convince people that the "First day of the week" does not belong in any translation. They have been brainwashed since little children to believe this nonsense because without it.....the theology of the Mainstream Church will come tumbling down (as it should).
I recall a day in 1959 when it finally dawned on me that the resurrection did not take place on Sunday. I wanted to shout out the evidence to the world......but I soon found out the world didn't want to know. They wanted to continue in their comfortable Churchianity with no rocking of the boat.
It's no different fifty years later. People are not comfortable with the idea of studying the issue themselves, and arriving at a logical conclusion. They would rather believe entrenched false traditions, fairy tales, impossible chronology, and take the word of clergy completely in agreement with an "anything anti Jewish" theology......i.e. (We can't show the resurrection on the Sabbath. That's the special day for the Jews....who killed Our Lord!)
Never mind that 99% of the Church of the First century, founded by the Apostles....were Jewish!