“When the Day of Pentecost had fully come, they were all with one accord in one place.” Acts 2:1
There’s several things that jump out at me about this verse: 1) The “Day of Pentecost”, 2) the words “fully come”, and 3) that they were all with “one accord”.
What was the “Day of Pentecost”? From what I have read, it took place 50 days after the Feast of the Firsfruits. According to J. Vernon McGee, the Feast of the Firstfruits speaks of the resurrection of Jesus Christ. “But now Christ is risen from the dead, and has become the firstfruits of those who have fallen asleep. For since by man came death, by Man also came the resurrection of the dead. For as in Adam all die, even so in Christ all shall be made alive. But each one is his own order: Christ the firstfruits, afterward those who are Christ’s at His coming. Then comes the end, when He delivers the kingdom to God the Father, when He puts an end to all rule and all authority and power. For He must reign till He has put all enemies under His feet. The last enemy that will be destroyed is death.” 1 Corinthians 20-26
The Passover speaks of the death of Jesus Christ: “…For indeed Christ, our Passover, was sacrificed for us. Therefore, let us keep the feast, not with old leaven, nor with the leaven of malice and wickedness, but with the unleavened bread of sincerity and truth.” 1Corinthians 5:7-8
The words “fully come”, again according to Dr. McGee, could be translated to mean “fulfilled”. The Passover was fulfilled in the death of Jesus Christ. The Feast of Firstfruits was fulfilled in the resurrection of Jesus Christ. Now, the Day of Pentecost, being “fully come” (aka fulfilled) means that it represented the fulfillment of something — the birth of the church, the day the church came into existence.
So, in order to understand the timeline…..
Jesus was crucified.
3 days later, He was resurrected.
For 40 days, He walked upon the earth, resurrected. (Acts 1:3)
He then ascended into heaven. (Acts. 1:9)
10 more days passed.
On the 50th day (Pentecost) the church was born and the Holy Spirit arrived.