What is the ruling on someone who experienced madhiy (pre-seminal fluid discharge), performed ablution (wudu'), and prayed, having forgotten to wash his private parts, and is he required to repeat his ablution and prayer?

If a man washes the impurity of madhy (pre-seminal fluid) but does not wash his male organs because there is no impurity on them, then his prayer is valid. Washing the male organs is not obligatory due to the emission of madhy; it is sufficient to wash only the place of impurity. If the impurity of madhy was present on the male organs and was not washed due to forgetfulness, the prayer is valid according to the majority of scholars, based on the saying of Sheikh al-Islam Ibn Taymiyyah: "So if he prayed and there was impurity on his body or clothes, and he did not know about it except after the prayer, he is not obliged to repeat it, according to the more correct of the two scholarly opinions... And it is the same whether he knew about it and then forgot it, or was ignorant of it from the beginning."