Show me from the day of Pentecost where the NT disciples, in the church, observed and practiced keeping the Sabbath as prescribed in the law. This is what happened at Pentecost when 3,000 souls were saved and added to the church...
Acts 2:46,47 46 And they, continuing daily with one accord in the temple, and breaking bread from house to house, did eat their meat with gladness and singleness of heart,47 Praising God, and having favour with all the people. And the Lord added to the church daily such as should be saved.
The only record we have of those keeping or gathering on the Sabbath after Pentecost were the practicing Jews, that Paul and others took opportunity to go in unto those gathered in the synagogue on the Sabbath, to preach Christ and to open the scriptures unto them concerning Christ. The epistles record no instructions to observe or keep the Sabbath for those who believed upon Christ, both of the Jew and the Gentile. If NT believers observed or gathered together on the Sabbath, it was not according to any mandate of the scriptures through the law but was of their own volition and accord to do so, being a common practice of the Jews to gather together on that day.
Here are verses in Acts
(Acts 1:12 KJV) Then returned they unto Jerusalem from the mount called Olivet, which is from Jerusalem a
sabbath day's journey.
(Acts 13:14 KJV) But when they departed from Perga, they came to Antioch in Pisidia, and went into the synagogue on
the sabbath day, and sat down.
(Acts 13:27 KJV) For they that dwell at Jerusalem, and their rulers, because they knew him not, nor yet the voices of the prophets which are read every
sabbath day, they have fulfilled them in condemning him.
(Acts 13:42 KJV) And when the Jews were gone out of the synagogue,
the Gentiles besought that these words might be preached to them
the next sabbath.
(Acts 13:44 KJV) And the next
sabbath day came almost the
whole city together to hear the word of God.
(Acts 15:21 KJV) For Moses of old time hath in every city them that preach him, being read in the synagogues every
sabbath day.
(Acts 16:13 KJV) And on
the sabbath we went out of the city by a river side, where prayer was wont to be made; and we sat down, and spake unto the women which resorted thither.
(Acts 17:2 KJV) And Paul,
as his manner was, went in unto them, and
three sabbath days reasoned with them out of the scriptures,
(Acts 18:4 KJV) And he reasoned in the synagogue
every sabbath, and persuaded the
Jews and the Greeks.