My father would never miss fasting

Reference: Siyar A’laam an-Nubalaa – Volume 11 / Page 223

‘Abdullaah ibn Ahmad ibn Hanbal said:

My father would never miss fasting [every] Monday and Thursday, and the three full moon days[1].

Footnote:

[1] The 13th, 14th and 15th days of every hijrah calendar month.