It was thought that God refused to send oracular dreams to His people when they failed to live up to His standards. A nation serious about obeying Him received visions in abundance. It was not unusual for Jewish mystics to seek dream answers from God. Usually his answers came in the form of a Bible verse. Some dreams promised that the Messiah would come when people obeyed the messages.
Jewish practice forbids the making of legal decisions based on dreams.
Although it was often thought that God preferred to bless the righteous prophets rather than the ordinary people with dreams and visions, the Bible is filled with dreams sent to pagans such as Pharaoh, Nebuchadnezzar, the Magi, Pilate's wife, etc. Nor can one be sure that one's dreams will contain anything pertinent to his situation. Moses himself had no need of dreams for God spoke plainly to him without images and their interpretations. False prophets were a constant problem in ancient Israel. They would pretend to receive the word of the Lord in dreams in order to draw attention and money to themselves.