Leviticus 23:21 - Joseph Benson’s Commentary on the Old and New Testaments

A holy convocation A sabbath, or day of rest, called pentecost; which was instituted, partly in remembrance of the consummation of their deliverance out of Egypt, by bringing them thence to the mount of God, or Sinai, as God had promised; and of that admirable blessing of giving the law to them on the fiftieth day, and forming them into a commonwealth under his own immediate government; and partly in gratitude for the further progress of their harvest, as in the passover they offered a thank-offering to God for the beginning of their harvest. The perfection of this feast was the pouring out of the Holy Spirit upon the apostles on this very day in which the law of faith was given, fifty days after Christ our Passover was sacrificed for us. And on that day the apostles, having themselves received the first-fruits of the Spirit, begat three thousand souls through the word of truth, as the first-fruits of the Christian Church.