IslamQA: Why do Muslims have to shower after sexual intercourse?

Asalam Walikum, Ramadan Mubarak! I have a question, why is it mandatory to take a shower right after sexual intercourse in order for the next prayer to be accepted? Especially if it's a sexually active married couple

The logic behind showering after sexual intercourse, and the logic behind the ablutions we perform before each prayer, is not explicitly clarified for us in the Quran or Sunna, so it is something we can only speculate about. Showering and ablution are part of what we call ṭahāra (“purity”) in Islam. Purity requirements exist in Judaism and Islam, and it also existed in the Christianity of Prophet Jesus and his brother James before the Christians abandoned the Torah. Christianity maintains one aspect of ṭahāra, which is the baptism that is required for each Christian to perform once in their lives. As Muslims, we perform baptism (ghusl) every time we lose our state of ritual purity, as in the case of sexual intercourse.

Purity requirements seem to be designed to impress upon the believer the fact that they belong to God. It is a physical act designed to make you feel you are in a new and purer state. In this way we are made to feel that we belong to a special nation of God that is characterized by a state of purity that other nations do not possess.

It is also a way of showing our submission to God. God says that we must do this in order to be pure, and by submitting to this requirement, we show our obedience and submission toward God even if the act in itself does not seem to have a particular logic behind it. The logic of it is the very fact that God demands it. God demands it, we obey. It is an expression of love and submission toward God.