Actually, as far as scripture is concerned, there are only two times mentioned with regard to anybody getting together on the first (day) of the week - John 20:19 and Acts 20:7. There is never any mention of them ever again being together on the first. The John reference has them together in a closed room after the crucifixion because they were afraid of their fellow Jews. Nothing is said about a worship service or day of rest. And it couldn't have been in recognition of the resurrection because at that time they didn't even believe that the resurrection had taken place.
And the Acts reference might very well have had them getting together to break bread with Paul because he happened to be in town and wanted to talk to them before he had to leave again. The "breaking of bread" can simply be saying that the disciples got together to eat a meal on this particular first day of the week . The phrase, "to break bread", does not have to refer to a religious service - unless it is specifically stated - but to dividing loaves of bread for a meal. "It means to partake of food and is used of eating as in a meal...... The readers [of the original New Testament letters and manuscripts] could have had no other idea or meaning in their minds" (E.W.Bullinger, Figures of Speech Used in the Bible, pp. 839,840.
But even if the breaking of bread mentioned always did refer to the Lord’s Supper, it had nothing to do with placing a special emphasis on the first (day) because Acts 2:46 says that they broke bread every day.
Also, a further explanation taken from B Ward Powers’ First Corinthians - An Exegetical and Explanatory Commentary:
"The expression 'the breaking of bread' found in Acts 2 was commonly used amongst the Jews to refer to the sharing of a meal in conscious religious fellowship, and this usage is found in the New Testament, not least in the Gospel by the same author as Acts and even elsewhere in the Acts."
"The significance of the religious aspect of the breaking of bread would be greatly heightened for the disciples in the light of the Last Supper, but this is not the same as saying that they held a ritual meal deliberately re-enacting the Last Supper in conscious obedience to the command of Christ, commemorating his death through eating bread and drinking a cup; and these features would be necessary if we are to regard the 'breaking of bread' as equating with the Lord’s Supper."
"Rather, the evidence indicates that in the New Testament the expression 'the breaking of bread' or 'broke bread' refers to the usual Jewish practice of prayer with which a hunger-satisfying meal commenced. When we recognize that references to the breaking of bread are not references to the Lord’s Supper, we see the significance of what we learn from Paul’s teaching in 1 Corinthians."
