They can come at any time and can last from just a few hours to months and even years. From time to time all of us get down, but this is not depression. Depression is ceasing to function in our daily chores and interests. It is giving up on our responsibilities.
Depression results from handling a down period sinfully.
Times of discouragement may be caused by any number of things, but depression comes when we give in to these down feelings. He had been used of God to lead the nation of Israel out of bondage. The people knew little else than a life of miracles. Still they griped and complained. Their focus was fixed on Egypt and the past rather than the future in the promised land.