Is an initial intention sufficient for combining the ghusl of Friday and janabah, and what is the ruling on acts of worship performed after a ghusl in which the intention for janabah was forgotten?

The intention (niyyah) is a fundamental condition for the validity of ghusl al-janabah (ritual bath after major impurity), and it must be simultaneous with the ghusl or precede it by a short time. If the intention for janabah is forgotten, and the person performing ghusl only intends for Jumu'ah (Friday) ghusl, then this ghusl is not sufficient for ghusl al-janabah according to the Maliki and Shafi'i schools of thought, because the intention for a non-obligatory ghusl cannot suffice for the intention of an obligatory ghusl.

Conversely, the Hanbalis, in one narration, hold that the intention for a recommended ghusl may suffice for an obligatory one.

Based on this, if the aforementioned ghusl is not sufficient for ghusl al-janabah, then all missed obligatory prayers after the aforementioned nocturnal emission must be made up, unless another ghusl for janabah was performed, in which case only the prayers between the two ghusls need to be made up.

It is prohibited for a person in a state of janabah to enter a mosque or recite the Qur'an before performing ghusl, except for a small portion for seeking refuge (ta'awwudh) and similar purposes. The intention is the resolve to perform an action at the beginning of its performance.