Acts 20:7

On the first day of the week. [1] The interpreters generally take notice with St. John Chrysostom, that the Christians, even at this time, must have changed the sabbath into the first day of the week, as all Christians now keep it. Which change (even as to the manner of keeping one of God's ten commandments) was made by the Church. --- To break bread, meaning the blessed sacrament, as it is commonly expounded. (Witham) --- St. Paul did here break bread on a Sunday, as it is broken in the sacrament of the body of Christ, and delivered a discourse to the people, both before and after the celebration of the divine mysteries. (St. Augustine, ep. lxxxvi. ad Casulanum.; Ven. Bede, in xx. Act.)

[BIBLIOGRAPHY]

Una Sabbati; that is prima sabbati, Greek: en te mia ton sabbaton. St. John Chrysostom says, (hom. Greek: mg.) Greek: kuriake en, erat dies Dominica.