The term Pentecost comes from the Greek Πεντηκοστή (Pentēkostē) meaning “fiftieth”. It refers to the festival celebrated on the fiftieth day after Passover, also known as the “Feast of Weeks” and the “Feast of 50 days” in rabbinic tradition.
It is interesting to note that on the day Moses came down from the mountain 3000 were slain, but on the day the church was established in Mount Zion, 3000 were saved. The law of Moses was a law of spiritual death because nobody could keep it perfectly, but the law of Christ is a law of life because it provides for the forgiveness of our sins.
Both events took place on the day of Pentecost. On this same day god verbally spoke the 10 commandments to Israel at Sinai. Then at Pentecost the Spirit wrote upon the tables of the heart.
Acts 1:4-5 And being assembled together with them, He commanded them not to depart from Jerusalem, but to wait for the Promise of the Father, “which,”He said,“you have heard from Me; for John truly baptized with water, but you shall be baptized with the Holy Spirit not many days from now.”
Acts 2:1; 41 When the Day of Pentecost had fully come, they were all with one accord in one place(all together and of one spirit)…then those who gladly received his word were baptized; and that day about three thousand souls were added to them.
2 Corinthians 3:2-3 You are our epistle written in our hearts, known and read by all men; clearly you are an epistle of Christ, ministered by us, written not with ink but by the Spirit of the living God, not on tablets of stone but on tablets of flesh, that is, of the heart.
Exodus 32:28 And the children of Levi did according to the word of Moses: and there fell of the people that day about three thousand men.