Paul went to the synagogue to preach Jesus Christ, not to have a Christian worship service.
Christians worshipped on the first day of the week, since this was the day Jesus rose from the dead.
the 7th day sabbath was a type of the rest we have in Christ, it points us to Jesus and was fulfilled by Him.
history is quite clear, the Catholic Faith received from the Apostles NEVER included keeping the 7th day sabbath.
>> “Christians worshipped on the first day of the week” <<
Not ever mentioned in the entire NT!
They worshipped at the beginning of the first day of the Hebrew week, which was in the evening of the pagan 7th day (saturday to pagans) at Havdalah, which marked the beginning of the work week. They “came togrther” at Havdalah to mark the end of their sabbath worship, every sabbath.
Sabbath worship continued until the terrorist thug Constantine turned his army against them.
No apostle of Yeshua ever deserted sabbath worship.
Yeshua’s present day remnant have returned to proper sabbath respect, while the lost will of course continue with their pagan nonsense on sunday, the day of the sun god Baal.
There was no other day ever commanded to have a worship service. The sabbath is and was the day. It didn't become official in the traditional church to worship on Sunday until a number of centuries after the death of Christ.
Christians worshipped on the first day of the week, since this was the day Jesus rose from the dead.
No doubt some turned their back on the sabbath so they wouldn't be misidentified as Jews who were hated by the Roman empire. But again it took several hundred years for the traditional church to abandon the holy days of Christ.
BTW, when "first day of the week" is referred to in scripture it almost always is literally "the first of sabbaths" or "one of the sabbaths". Considering the timing of the phrase it's likely this was referring to the count of sabbaths between Passover and Pentecost.
the 7th day sabbath was a type of the rest we have in Christ, it points us to Jesus and was fulfilled by Him.
This is certainly a doctrine that developed over time, but it's not biblical.
history is quite clear, the Catholic Faith received from the Apostles NEVER included keeping the 7th day sabbath.
The apostles delivered what had been delivered to them from Christ....worship and honor His holy days. Somewhere along the way people decided their own hides were more important then scripture and changed things around.