What is the most virtuous voluntary fast after Ramadan?

Primary text

The most virtuous voluntary fast after the month of Ramadan is the fast of the month of Allah, Muharram. This is established by the report from Abu Hurayrah stating the Prophet Muhammad, peace be upon him, said: 'The best of fasting after the month of Ramadan is the month of Allah, Muharram.' This hadith was narrated by Abu Dawud and al-Tirmidhi, who classified it as Hasan (good).