Prior to Islam:

The day of ‘Aashuraa was significant even prior to Islam. The Ambiyaa (‘alaihimus salaam) would observe fast on this day.

عن أبي هريرة رضي الله عنه أنه قال: قال رسول الله ﷺ: يوم عاشوراء يوم كانت تصومه الأنبياء، فصوموه أنتم

Hadhrat Abu Hurairah RA reports that the Messenger of Allah ﷺ said: The Prophets used to fast on the day of Aashura, so you should also fast. [Musannaf ibn Abi Shaybah]

During the time of ignorance, the Quraish would change the kiswah (covering) of the Ka’bah on the day of ‘Aashuraa and observe fast on it.

عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانُوا يَصُومُونَ عَاشُورَاءَ قَبْلَ أَنْ يُفْرَضَ رَمَضَانُ، وَكَانَ يَوْمًا تُسْتَرُ فِيهِ الْكَعْبَةُ، فَلَمَّا فَرَضَ اللَّهُ رَمَضَانَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ “‏ مَنْ شَاءَ أَنْ يَصُومَهُ فَلْيَصُمْهُ، وَمَنْ شَاءَ أَنْ يَتْرُكَهُ فَلْيَتْرُكْهُ

Narrated Hadhrat Aisha RA: The people used to fast on Aashura (the tenth day of the month of Muharram) before the fasting of Ramadhan was made obligatory. And on that day the Ka`ba used to be covered with a cover. When Allah made the fasting of the month of Ramadhan compulsory, Allah’s Messenger ﷺ said, “Whoever wishes to fast (on the day of Aashura) may do so; and whoever wishes to leave it can do so.” [Bukhari – 1592]

Thus Rasulullah ﷺ would observe the fast of Aashura before Nubuwwat as well.

عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانَ يَوْمُ عَاشُورَاءَ تَصُومُهُ قُرَيْشٌ فِي الْجَاهِلِيَّةِ، وَكَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَصُومُهُ

Narrated Hadhrat Aisha RA: Quraish used to fast on the day of Aashura in the Pre-Islamic period, and Allah’s Messenger ﷺ too, used to fast on that day. [Bukhari – 2002]

Moosa (‘alaihis salaam):

After migrating to Madeenah Munawwarah, Rasulullah ﷺ witnessed the Jews of Madeenah Munawwarah fasting on the day of Aashura. When Nabi ﷺ inquired from them as to the reason for their fasting, they explained that it was on this day that Allah Ta‘ala saved Nabi Moosa AS and the Bani Israel (from the tyranny and oppression of Fir‘aun) and drowned Fir‘aun and his army. So, Nabi Moosa AS observed fast on this day, out of gratitude to Allah Ta‘ala. Rasulullah ﷺ said,

عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ قَدِمَ النَّبِيُّ صلى الله عليه وسلم الْمَدِينَةَ، فَرَأَى الْيَهُودَ تَصُومُ يَوْمَ عَاشُورَاءَ، فَقَالَ ‏”‏ مَا هَذَا ‏”‏‏.‏ قَالُوا هَذَا يَوْمٌ صَالِحٌ، هَذَا يَوْمٌ نَجَّى اللَّهُ بَنِي إِسْرَائِيلَ مِنْ عَدُوِّهِمْ، فَصَامَهُ مُوسَى‏.‏ قَالَ ‏”‏ فَأَنَا أَحَقُّ بِمُوسَى مِنْكُمْ ‏”‏‏.‏ فَصَامَهُ وَأَمَرَ بِصِيَامِهِ‏

Narrated Ibn `Abbas RA: The Prophet ﷺ came to Medina and saw the Jews fasting on the day of Aashura. He asked them about that. They replied, “This is a good day, the day on which Allah rescued Bani Israel from their enemy. So, Moosa fasted this day.” The Prophet ﷺ said, “We have more claim over Moosa than you.” So, the Prophet ﷺ fasted on that day and ordered (the Muslims) to fast (on that day). [Bukhari – 2004]

Nabi Nooh (‘alaihis salaam):

In a narration of Musnad Ahmad, the Jews also explained to Rasulullah ﷺ that this was the day on which the ark of Nabi Nooh AS had settled on Mount Judi. Hence, Nabi Nooh AS fasted on it out of gratitude.

Gratitude for Favour:

When a believer achieves something, he does not boast over it and attribute the achievement to himself, rather, he believes it to be a favour of Allah Ta‘ala and thus is more grateful and loyal to Him. This was the pattern in the lives of all the Ambiyaa (‘alaihimus salaam). The glaring example of this in the life of Rasulullah ﷺ was the humility that Rasulullah ﷺ displayed on the occasion of the conquest of Makkah Mukarramah.

We will continue with this discussion on fasting tomorrow in sha Allah.