The Prophet ﷺ once said:
"Fasting on the day of Ashura expiates the sins of the past year."
The 10th day of Muharram carries immense spiritual weight. When the Prophet ﷺ arrived in Madinah, he found the Jews fasting on this day. He asked why, and when they explained its significance, he said Muslims should fast it too - and even encouraged fasting the 9th with it for extra reward.
This single fast can wipe away a year's worth of mistakes, slips, and shortcomings.
