Jahannum is surrounded by desires and passions

عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللهُ عَنْهُ قَالَ قَالَ رَسُولُ اللهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ حُفَّتِ النَّارُ بِالشَّهَوَاتِ، وَحُفَّتِ الجَنَّةُ بِالمَكَارِهِ

Abu Hurairah (Radiyallahu anhu) narrates that Rasulullâh (Sallallahu alayhi wasallam) said, “The Fire is surrounded by all kinds of desires and passions, while Paradise is surrounded by all kinds of disliked undesirable things.” (Bukhari)
The Fire is surrounded and covered by desires and passions. What is the meaning of nafs? Moulana Thanwi (Rahimahullah) has explained so beautifully, Natural desires which are not in accordance to the Shariah. 

A person has sexual desires to fulfil. There is no harm. He can fulfil it with his permissible wife. A person desires to eat. There is no harm in eating halâl food if the time is correct e.g. one is not  fasting in the days of Ramadhân.

Yes, one must not engage in unlawful sexual relationships. One must not eat harâm food. All of these forbidden desires surround Jahannum. When a person perpetrates them, he enters himself into Jahannum. 

On the other hand, Jannah has been surrounded by makârih i.e. such actions which are not really liked by the nafs, for example, awakening for salâh, going to the masjid, abstaining from sins like backbiting, evil glancing, etc. If a person strives against his desires, he will enter Jannah. 

This is for a mubtadi (beginner in the path to Allâh Ta'ala). When a person makes effort, then these evils become disliked to him; and good actions become beloved to him. In the beginning, pornography is liked by a person. After making effort, it becomes extremely bitter to even go near such filth. Waking up for tahajjud becomes enjoyable. To sit and make dhikr is generally difficult upon a person. But once a person gets in the habit of making dhikr, he gains so much enjoyment that it becomes difficult to leave it out. 

Moulana Umar Saheb Palanpuri (Rahimahullah) once said, “If you people gain the enjoyment of dhikr, then it will become difficult for a person to go out for ghust.” As long as this fervour is not created, a person cannot sit for a few minutes to make dhikr. If a person does not rectify himself, he remains in this condition for his whole life where sins are enjoyable to him, and good actions are a burden.
 
As long as this fervour is not created, a person cannot sit for a few minutes to make dhikr. If a person does not rectify himself, he remains in this condition for his whole life where sins are enjoyable to him, and good actions are a burden. Allâh Ta'ala states,  Perhaps you dislike something whereas it is good for you. And perhaps you love something whereas it is evil for you. (Baqarah verse 216) 

A person who controls his desires is successful. An easy example to understand this: A person is in the fourth year of his studies. He desires to miss classes, run around and waste time. However, at the end of the year, he will fail, and will have to repeat the year. On the other hand, the person who is punctual in class, learns diligently and stays awake till two o’ clock during exams, is successful. Desires have been placed in every person. 
Allâh Ta'ala  states, Then He inspired within it evil and the ability to abstain. (Shams verse 8) 
Those who follow the evil temptations of the nafs will fall headlong into Jahannum, whilst those who control themselves will enter into Jannah. 

(Hazrat Moulana Abdul Hamid Ishaq Saab (Daamat Barakaatuh)

Reference: 

  • Lessons from Bukhari