Because he was a Jew and wanted to worship???? Maybe Priscilla and Aquila had an errand to run or something.
If you notice further down in verses 24-26 Priscilla and Aquila are now in the synagogue listening to a Jew named Apollos....and then invite him to there home after services.
Why are you so adamant about observing the Catholic Sabbath in light of scriptural proof it is wrong?
In the heat of the debate my fingers err.
and then invite him to "their" home.......
Apollos apprears to be dealing in the synagogue in much the same way as Paul, except without the knowledge. This was not a Christian worship service. That obvious by the fact the Priscilla and Aquila took him aside to help him calrify his views on Jesus Christ.
Why are you so adamant about observing the Catholic Sabbath in light of scriptural proof it is wrong?
Your "proof" amounts to nothing. The universal (catholic) church has interpreted the NT accounts for 2 millennia accurately regarding the change of the weekly sabbath from the last day to the first day. A few cults have opposed this view, but their exegetical efforts have amounted to straw.
Why do you suppose we again see Gentile Christians worshiping in the synagogues with the Jews?
God fearing greeks was a term used to describe gentiles who were following in Jewish ways but had not yet become full proselytes. It is not a synonym for "Christian".
Whether it be arians who deny the deity of Christ, seventh day sabbatarians to seek to liave according to old covenant shadows, or chiliasts who look for a fleshy, judaistic millenium, thankfully such views have been few and far between.