This will be the punishment of Egypt and of all nations that do not go up to celebrate the Feast of Tabernacles.

Then all who survive from all the nations that came to attack Jerusalem will go up annually to worship the King, the Lord who rules over all, and to observe the Feast of Tabernacles. ¹ 

If the Egyptians will not do so, they will get no rain – instead there will be the kind of plague which the Lord inflicts on any nations that do not go up to celebrate the Feast of Tabernacles.