[Machine] The day of Ashura used to be observed as a fast by the Quraysh in the pre-Islamic era, and the Prophet Muhammad ﷺ also used to fast on this day during that time. When the Prophet Muhammad ﷺ arrived in Madinah, he continued to fast on this day and ordered others to also observe the fast. However, when the obligatory fast of Ramadan was established, it became the main priority, and the fast of Ashura was left as optional. So, whoever wishes to fast on this day may do so, and whoever wishes to leave it may do so.
كَانَ يَوْمُ عَاشُورَاءَ يَوْمًا تَصُومُهُ قُرَيْشٌ فِي الْجَاهِلِيَّةِ وَكَانَ رَسُولُ اللهِ ﷺ يَصُومُهُ فِي الْجَاهِلِيَّةِ فَلَمَّا قَدِمَ رَسُولُ اللهِ ﷺ الْمَدِينَةَ صَامَهُ وَأَمَرَ بِصِيَامِهِ فَلَمَّا فُرِضَ رَمَضَانُ كَانَ هُوَ الْفَرِيضَةُ وَتَرَكَ يَوْمَ عَاشُورَاءَ فَمَنْ شَاءَ صَامَهُ وَمَنْ شَاءَ تَرَكَهُ