Why is prayer invalidated if Surat Al-Fatiha is recited incorrectly, whether due to ignorance or forgetfulness, despite Allah overlooking mistakes and forgetfulness for the Ummah of Muhammad (peace be upon him), and His (the Most High) saying: "Our Lord, do not take us to task if we forget or make a mistake"?

"A melodic error (laḥn) in Al-Fatiha that does not alter the meaning does not invalidate the prayer, even if it involves substituting one letter for another, should the person be unable to learn otherwise. Similarly, regarding common difficulties with letters that have close points of articulation (makhārij), many scholars show leniency and do not consider the prayer invalid. However, if someone omits a verse from Al-Fatiha out of forgetfulness and then remembers, they must make up for what was missed; otherwise, their prayer is not valid. This is akin to someone who prays without ablution out of forgetfulness; they must repeat the prayer. One's obligation regarding the conditions (shurūṭ) and pillars (arkān) of prayer is not fulfilled except by performing them. If one omits something from these out of forgetfulness, they are still required to perform it. This does not contradict the ease of Sharia; rather, it is part of its ease that one is not sinful for forgetting, but the commanded act remains a duty until it is performed."