The ruling on repeating istinja' (cleaning oneself after relieving oneself) with every wudu' (ablution)

Question:
And among the detailed explanations is that one returns to washing what he desires to wash with at every emission, that he washes with it after the state of impurity, and that he washes after a certain amount of water, saying, “Wash thus and thus,” and that he performs a specific washing in the presence of others.

Answer:
It is sufficient to wash the exit point where the impurity is. The texts specifically mention washing the penis and the two buttocks, meaning the two sides of the exit. If a person has a discharge, he washes his penis and his two buttocks, as stated in the hadith. As for urine, no, he washes the head of the penis, the exit point, and that is sufficient. If he performs istinja' (cleaning oneself after relieving oneself), he does not repeat it with every wudu' (ablution). Istinja' is only required when something exits the body. If something exits, whether urine or feces, he performs istinja' or istijmar (cleaning with stones), and then he remains in that state of istinja' and istijmar until another discharge exits from him. He does not repeat it with every wudu' (ablution), because it is not one of the limbs of wudu' (ablution). Wudu' (ablution) refers to the limbs that Allah named in the verse These are the limbs of wudu' (ablution). As for istinja' (cleaning oneself after relieving oneself), it is not one of the limbs of wudu' (ablution); rather, it is merely the removal of impurity. If it is removed once, that is sufficient.