Exodus 23:14-17

CLV(i) 14 Three times shall you celebrate to Me in the year: 15 you shall observe the celebration of unleavened cakes; seven days shall you eat unleavened cakes, just as I instructed you, at the appointed time in the month Aviv, for in it you went forth from Egypt, and none shall appear before Me empty-handed. 16 also observe the celebration of the harvest of the firstfruits of your yields from what you are sowing in the field: and observe the celebration of ingathering at the going forth of the year, when you gather your yields from the field. 17 Three times in the year every male of you shall appear before the Lord Yahweh.
Reformed Dating