Importance of Pentecost
The day of Pentecost as referenced in Acts 2 was a result of fifty days from the Passover Sabbath (πεντηκοστή pentēkostē fiftieth from Passover, Strong’s Dict.). This day was counted from “the morrow of the Sabbath” (Lev.23:15) when the omer of barley harvest i.e. “wave sheaf” was first cut. The count of these weeks was to start the day the sickle cut that first wave offering (Dt.16:9). This barley harvest was to be over and done within 7 weeks i.e. 49 days from which the “Feast of Ingathering” (Ex.23:16) or “Day of First Fruits” (Num.28:26) as they were known under the Old Testament could begin. This day of Pentecost marked the beginning of the wheat harvest, hence the term “first fruits”. It is no coincidence, in my humble opinion, that the two different corns represent the Old (i.e., barley) and the New Testaments (i.e., wheat) [any crop farmer will attest barley always precedes wheat in harvest times].
A simple count of 49 days beginning “the morrow of the Sabbath” will, without exception, bring one to the first day of the week that we call Sunday. This day marked the beginning of the church, of which there is, without exception, only one (Eph.4:4).
It goes without saying this church needed entry conditions explained i.e. the plan of salvation given by Peter upon request of those who crucified Jesus (Acts 2:37—41). In addition, this church was instructed via the “apostle’s doctrine” regarding fellowship and worship (Acts 2:42-47). It is important to note that the “breaking of bread” in verse 42 differs from “breaking bread from house to house” found in verse 46. The former concerns the immediate context with the Lord’s Supper memorial for “the breaking” is tn klasis i.e. the fracture, the specific act of breaking the specific bread [the Greek places the definite article tn before breaking and tov before bread indicating specificity] that Adam Clarke points out: “Breaking of bread was that act which preceded a feast or meal, and which was performed by the master of the house, when he pronounced the blessing – what we would call grace before meat”. The word is employed by Matthew in chapter 26:26 where Jesus, the Master, “took the bread, blessed it and broke [klasis] it” because it represented His body upon the soon to be realised cross, a solemn and shameful (Gal.3:13) event. This in contrast with the latter “break” is klaō i.e. to generically break which the immediate context of the remainder of the verse says “they ate their food with gladness and simplicity of heart”. They were simply breaking the food apart to eat it with gladness of fellowship together with people of common salvation.
This having been said indicates the absolute importance of the first day of the week for the church to assemble for authorised worship and fellowship.