Book of Numbers
Some people complain about God, and God punishes them (e.g. by giving one leprosy, a nasty disease). The complaints deal with the lack of good food and water, and the difficulty of life in the desert. The food they are given is called manna and quail, which God sends raining down from the sky above. Their ingratitude is an example of the human inclination of moaning rather than being thankful for what one has, which in their case was the ultimate liberation from centuries of wicked slavery. The Levites help Moses pray at the tabernacle.