It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) concerning this saying of Allah Almighty: "And there is none of you except he will come to it" [Surah Maryam: 71] , that he said: "The Sirat over Hell will be like the edge of a sword (thin and sharp). The first group will pass like lightning, the second like the wind, the third like the finest horses, and the fourth at the pace of the finest camels and cattle, while the angels will be supplicating: 'Rabbi sallim sallim' (O Lord, grant safety, grant safety)." This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.