Maybe it was taken as a given. Something so ingrained it did not have to be "commanded". In fact they probably met as often as they could. But they would have especially met on the Sabbath if they were physically able.
"Maybe?!" You mean such a cardinal practice is without any actual example of the NT church keeping it, while the Holy Spirit shows the disciples meeting on the first day, and treating that the sabbath as part of the ceremonial law.
In fact they probably met as often as they could. But they would have especially met on the Sabbath if they were physically able.
Which, as with the assertion that Abraham kept the 7th day, is only assumed, which absence of substantiation leaves your required observance untenable as one.