Q 3: What
is the ruling on forgetting to make Isti`adhah (saying: "A`udhu-Billahi mina Al-Shaytan -ir-Rajim [I seek refuge with Allah from the accursed Satan]") during or after Salah?
Observing Isti`adhah is Sunnah (action following the teachings of the Prophet). There is nothing wrong with not saying it, whether intentionally or inadvertently, in Salah.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.