From William Willimon’s comments on Acts 20:
This is one of the New Testament’s earliest definite references to weekly Sunday worship. The Christians have continued to gather in the synagogue — unless they have been expelled. But they also apparently gather on Sunday, the first day of the Jewish work week, the day which is for Christians a day of resurrection. The church Luke describes is thus moving toward a distinct day of worship of its own, a day symbolizing clearly that while there is much uniting the church with Judaism there is also much dividing it from Judaism. The day of worship, as well as the stories and actions which occur around the table, constitutes the church as a distinct entity, gives it an identity, keeps reminding the church of who it is. Sunday is the Lord’s Day when Christians gather to celebrate the Lord’s Supper. Around the table in the gathering for worship, in the breaking of bread, Christians sustain one another through the presence of God as experienced at the table. As the Reformers agreed, word and sacrament belong together. Here is where the Body of Christ is made visible (1 Cor. 11:17-32). Here is where the Body re-forms, receives nourishment and encouragement in this weekly rhythm of renewal and reiteration of our identity as God’s family.