Sexual fantasies are a type of thought that may cross a person’s mind. Whatever a person thinks of to himself, if he does not allow it to take root or persist in thinking about it, is forgivable, according to scholarly agreement.
Passing thoughts are forgivable, but the individual must ward them off and not get carried away in dwelling on them.
It is not permissible for the Muslim to consciously bring such thoughts to mind and become absorbed in dwelling on them, and it is also not permissible for him to let himself get carried away in thinking about things that cross his mind, for that will lead him to what is haraam.
See the answer to question no. 84066 .
Secondly:
Envy (hasad) is a blameworthy characteristic, and the Muslim should strive to rise above it. Shaykh Ibn ‘Uthaymeen (may Allah have mercy on him) said: It was said that envy means wishing that that with which Allah has blessed someone else will be taken away from him, and it was said that it means resenting that with which Allah has blessed someone else.
The former definition is the well-known view among the scholars, and the latter is the view of Shaykh al-Islam Ibn Taymiyah (may Allah have mercy on him). Simply resenting that with which Allah has blessed other people is regarded as envy.
Envy is haraam, because the Prophet (blessings and peace of Allah be upon him) forbade it. It is one of the characteristics of the Jews who envy people for what Allah has given them of His bounty, and the harm it causes is extensive. End quote from Fataawa Noor ‘ala ad-Darb (24/2).
