The ancient Chinese believed that dream pictures foretold the exact opposite of what would actually happen. As early as 1601 modern dream books were printed to help the public interpret their own dreams. Jewish rabbis considered many dreams prophetic. A person could avoid the fulfillment of a bad dream by prayer, fasting, and repentance, or by announcing to three people that he had indeed had a good dream rather than a bad one. To prove this proverb Rabbi Banah had one dream interpreted by twenty four different people and every one of the interpretations came true.
Biblical dreams differ significantly from other dreams.
Most of the time they are spoken messages delivered by an angel or God Himself. When symbolism is involved, the dreams remain fairly straight forward and may even include an angelic interpretation. Bad dreams were thought to come from bad angels. Prophetic dreams would abound in the last days due to the outpouring of the Holy Spirit upon all flesh. However, the king protested that he had not touched Sarah and had received her as Abraham's sister - not his wife.