Numbers 10:10-11

10You must make sounds with the trumpets on your happy days, too. And you must make sounds with the trumpets at your regular festivals and on the first days of your months. And you must make sounds with the trumpets over your burnt offerings, and over your friendship offerings. God will hear and he will remember you. I am the Lord your God.’

11In the second year, in the second month, on the 20th day of the month, the cloud went up. It went away from God's Tent of Meeting.