The prophet that had prophesied about the day of Pentecost was Joel.
Explanation:
Pentecost is a Christian feast celebrating the Holy Spirit being given to the apostles in Jerusalem. According to the Bible, this was the first time tongues had appeared (a sign of the fulfillment of the Holy Spirit) and that day nearly 3,000 people were baptized in the name of Jesus for the remission of sins. Pentecost falls 10 days after Christ's Ascension Day. This celebration was envisaged by Joel, who wrote that the Holy Spirit would came from heaven to forgive sins on 800 BC.
