📖Sahih Muslim 1163 b
Abu Huraira (Allah be pleased with him) reported that the Messenger of Allah ﷺ was asked: Which prayer is most excellent after the obligatory ones? He replied: “The prayer in the middle of the night.” Then he was asked: “Which fast is best after Ramadan?” He replied: “Fasting in Allah’s month, al-Muharram.”

Description:
This hadith highlights two powerful voluntary acts: Tahajjud (night prayer) and fasting in Muharram. These are not obligatory, but the Prophet ﷺ labeled them the best after the required duties. Night prayer reflects deep sincerity, worship done when the world sleeps, showing love for Allah without seeking attention. Fasting in Muharram, especially on the 10th (Ashura), links back to the tradition of Prophet Musa (AS) and Allah’s deliverance of Bani Israel, making it spiritually significant and historically honored.

Quranic Context:

📖Quran 2:50
And [remember] when We parted the sea for you and saved you and drowned the people of Pharaoh while you were looking on.
This refers to how Allah saved the Israelites from Pharaoh by parting the sea, a divine rescue that took place on the 10th of Muharram.

Now, about fasting in Muharram, some may argue that the Qur’an doesn’t explicitly mention it. Here’s the answer:

📖Quran 59:7
And whatever the Messenger gives you, take it, and whatever he forbids you, refrain from it.
So, when the Prophet ﷺ says that fasting in Muharram is best after Ramadan, that becomes a legitimate source of spiritual guidance, even if not detailed in the Qur’an.

Summary:
The Qur’an sets the foundation, the Prophet ﷺ gives the application. Fasting in Muharram isn’t made up, it’s rooted in the Qur’an’s honor of sacred months, then clarified and emphasized by the Prophet ﷺ. Ignoring the Sunnah is like reading a manual but refusing to listen to the expert who wrote it.