Is it permissible for the one afflicted by whisperings (waswas) to adopt the view of those who consider avoiding impurity in prayer to be a Sunnah?

There is no harm in adopting the view of those who consider the removal of impurities (najāsa) to be Sunnah (definition), in order to alleviate obsessive doubts (waswās). In the Maliki madhhab (definition), there is a strong opinion that whoever intentionally abandons a Sunnah must repeat the prayer perpetually. In this case, the difference of opinion regarding whether the removal of impurities is obligatory or Sunnah becomes a semantic disagreement. However, if it is said that one who intentionally abandons a Sunnah only repeats the prayer within its prescribed time, then the disagreement becomes substantive. Ibn Rushd stated that an intentional and capable person must always repeat the prayer obligatorily, whether the removal is deemed obligatory or Sunnah, whereas Al-Qurtubi held that one who repeats the prayer for impurities only within the prescribed time adheres to the view of it being Sunnah. We recommend consulting Ibn Kathir's "Al-Bidāyah wa an-Nihāyah" and Sheikh Ali Al-Sallabi's books on history.