Rasoolullah (Sallallahu alaihi wasallam) said:
“Hellfire is screened by sensual pleasures whilst Paradise is screened by difficulties.”
(Bukhari, Muslim – Mishkaat)
Explaining the above Hadeeth, Imam Nawawi (Rahmatullahi alaih) said: “Jannat is reached through undergoing difficulties and Jahannam is reached by indulging in sensual pleasures. In this manner the two [Jannat and Jahannam] are screened. One who lifts the screen reaches the screened. Lifting the screen of Jannat is by tackling hardships, whilst lifting the screen of Jahannam is by engaging in sensual pleasures.
“The ‘difficulties’ are: exertion in Ibaadat, constancy in acts of obedience, perseverance in the face of sensual pleasures, etc. “The ‘sensual pleasures’ which serve as a screen for Hellfire apparently are such pleasures which are haraam, such as drinking liquor, committing zina, backbiting, etc. Lawful pleasures are excluded from this.”