A detailed explanation of this Sheikh has been made by Shaikh`Atiyyah Saqr, former head of Al-Azhar Fatwa Committee, who stated:
However, there are certain facts one should know, and all of them are parts of Hadiths quoted from the Prophet, peace and blessings be upon him, they are:
First Hadith- A vision is from Almighty Allah (it’s a form of divine inspiration) whereas a dream is from Satan. When any one of you have a bad dream, let him/ her spit out (without saliva) to the left side and recite the two ‘Protective Surahs’ (An-Nas and Al-Falaq) and the dream will not harm him/her, Allah willing.
Second Hadith- At the approach of the Hour, the Muslim will have a true vision, and honesty will help him to have the clearest and truest vision. Moreover, seeing a true vision is the 45th degree of prophethood.
Vision is of three kinds: the good one with glad tidings from Allah; the bad dream, which is from Satan to invade hearts with sadness; the third one is the effect of an aforethought matter. So if any one of you sees something sad in a vision, he should offer two rakats in prayer and never reveal it to anyone.
Third Hadith- The Prophet said that if anyone sees him in his vision, he has truly seen him, for Satan can never disguise himself in the honorable form of the Prophet, peace and blessings be upon him.
To conclude, the interpretation of dreams is not an experimental knowledge to pass on to people, generation to generation. It is a divine gift bestowed on whom Allah wills. Prophet Joseph’s talent of interpreting dreams is a case in point.
Finally, we can say that dreams or visions are not sources of legislation, so it shouldn’t be threatening or frightening to anybody and it doesn’t have a binding force of legal rules.”