Answered by Shaykh Faraz Rabbani
Question: If I was a Shafi`i and then became Hanafi, do I need to make-up witr prayers that I prayed as one cycle (rak`at)? Can I follow the Shafi`i position on leaving the sunna prayers when obligated to perform make-up prayers, and if yes then do I have to follow the Shafi`i school in rules of ritual purity (tahara)?
Answer: Walaikum assalam,
There is a legal principle that, “An ijtihad is not invalidated by another.” [Kasani, Bada i` al-Sana`i; Abd al-Aziz al-Bukhari, Kashf al-Asrar; and almost every major Hanafi fiqh work, with similar wordings]
From this principle, a derived ancillary principle is that, “Following a valid ijtihad in the past does not need to be rectified by one s following different ijtihad later on.”
As such, if the person prayed 1-rakat witr as a Shafi`i, or even omitted praying it, no makeup would be necessary if one later became a Hanafi.
Of course, if one chooses to make it up, out of caution or taqwa, one is rewarded. It is a sunna to makeup missed witrs in the Shafi`i and Hanbali schools. [Ibn Hajar, Tuhfa al-Muhtaj; Buhuti, Kashshaf al-Qina`]
Leaving the Sunna to Perform Make-Up Prayers
If one is a Hanafi, It would be best to continue to follow your own school, and to seek the assistance of Allah and simply perform the sunnas. If you seek something for the sake of Allah, with sincerity, Allah will certainly grant you assistance therein.
If you try and still find it unreasonably difficult, then you can follow the Shafi`i position regarding non-performance of current sunnas without having to follow the Shafi`i school in matters of purification and prayer.