And we used to deny the Day of Recompense, until the certainty (Al-Yaqin) came to us.meaning, death.This is as Allah says,وَاعْبُدْ رَبَّكَ حَتَّى يَأْتِيَكَ الْيَقِينُand worship your Lord until there comes unto you the certainty. (15:99)The Messenger of Allah said,أَمَّا هُوَ يعني عثمان بن مظعون فَقَدْ جَاءَهُ الْيَقِينُ مِنْ رَبِّهConcerning him verily, Al-Yaqin (death) came to him from his Lord."Allah then says,فَمَا تَنفَعُهُمْ شَفَاعَةُ الشَّافِعِينَ