Deuteronômio 16

Deuteronômio 16:10

An offering of "first fruits," that is, from the beginning of the harvest, is commanded. If you remember well, the law commands this is to be done on the day of Pentecost. This was obviously given to them as a "shadow," but the truth was reserved for us. For on the day of Pentecost, after they offered up the sacrifice of prayers, the church of the apostles received the first fruits of the coming of the Holy Spirit. — HOMILIES ON LEVITICUS 2.2.5