Arabic (Original)
وَعَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ قَالَ لِسُرَادِقِ النَّارِ أَرْبَعُ جُدُرٍ كَثُفَ كُلِّ جِدَارٍ مِثْلُ مَسِيرَةِ أَرْبَعِينَ سَنَةً.
English Translation
And from the Messenger of God (peace and blessings be upon him), that he said: "The enclosure of the Fire has four walls, the thickness of each wall being like a journey of forty years."