[12].Surah Yusuf [Joseph] : Ayat 41

Ayat 41. "O two companions of the prison! (Interpretation of your dreams are) As for one of you, he (as a servant) will pour out wine for his lord (king or master) to drink; and as for the other, he will be crucified and birds will eat from his head. Thus is the case judged concerning which you both did inquire." 

Hazrat Abu Qatadah (May Allah be pleased with him) reported: The Prophet  [SAWW](PBUH) said, "A good vision (dream) is from Allah and a bad dream is from the Satan. He who sees something in a dream that he dislikes, should spit thrice (without saliva) on his left, must seek Allah's Refuge from the evil of the Satan (i.e., by saying: A`udhu billahi minash-Shaitanir-Rajim). Then it will not harm him.''

[Al-Bukhari INTERPRETATION OF DREAMS, Book 87, Hadith # 124]. 

Lesson : as mentioned above in Surah Yusuf Ayat 41. ""O two companions of the prison! (Interpretation of your dreams are)." there are good dreams and bad dreams. This Hadith shows us what to do in order to avoid the evil of Satan who cannot harm anyone except by Allah's leave.