The Bible mentions the day of Pentecost, and therefore, it is good to define what this means. Pentecost is a Greek word meaning “fifty.” Fifty days had elapsed from the Resurrection of Christ until the descent of the Holy Ghost. It comes from the Feast of Weeks mentioned in Leviticus 23:15-16, to which, the people waited fifty days/seven weeks after Passover (in which we commemorate that Christ was sacrificed, for He is the Passover lamb), and then brought a meat offering to the Lord. (It was 40 days from the Resurrection of Jesus Christ until He ascended into Heaven.)
The Day of Pentecost, similar to the Feast of Weeks, would celebrate the first fruits of Christ’s ascending into Heaven, similar to how the Feast of Weeks would celebrate the first fruit of wheat harvest, primarily to thank God for the blessings of the harvest. This was a day the apostles liked to celebrate (Acts 20:16; 1 Corinthians 16:8).