Why Does Fasting on the Day of ‘Arafah Expiate the Sins of 2 years Whilst ‘Ashuraa Expiates That of 1 Year?

الحمد لله رب العالمين، وصلى الله وسلم على نبينا محمد وعلى آله وأصحابه أجمعين، أما بعد

Ibn Al-Qayyim (rahimahullaah) said:

“If it is said: ‘why does ‘Ashuraa expiate (the sins) of a year and the day of ‘Arafah expiates that of two years?’

Then it is said that there are two aspects to that:

The first of them: is that the day of ‘Arafah is in a sacred month; and before it is a sacred month; and after it is a sacred month – in contrast to ‘Ashuraa.

The second: is that fasting on the day of ‘Arafah is from the exclusive characteristics of our legislation – in contrast to ‘Ashuraa.

Hence it is doubled by way of the blessings of Al-Mustafaa (i.e. the Prophet Muhammad) sallallaahu ‘alaihi wa sallam – and Allaah Knows best.”

(Taken from: Badaa-i’ Al-Fawaa-id vol 4 p.1667)