Exodus 8:9, 10
Moses said to Pharaoh, "You may have the honor over me. When shall I pray for you and your officials and your people that the frogs (except for those in the Nile) may be taken away from you and your houses?" . . .

Exodus 10:23
No one could see each other, and for three days no one left his place. Yet all the Israelites had light in their dwellings.

2 Samuel 24:13
So Gad went and said to David, "Shall you endure three years of famine on your land, or three months of fleeing the pursuit of your enemies, or three days of plague upon your land? Now then, think it over and decide how I should reply to Him who sent me."