If a Muslim man or woman prays in a garment on which there is some impurity, regardless of the type of garment, and he did not remember that until after he had finished praying, then his prayer is valid according to the correct opinion.

There is nothing wrong with praying on the sidewalk because the mosque is full and there is no other place to pray.

Praying `Isha’ before Maghrib is not valid. If this happens mistakenly, one must first complete the missed Maghrib prayer, then repeat `Isha’ to fulfill the obligations in the correct order.

Unintentional miscalculation of menses is not a sin. If a woman thinks that she has become pure and starts praying and fasting, then she realises that she is still menstruating, then she has to stop praying and fasting until she becomes pure, and she should make up the obligatory fasts that she observed during that time.

The meaning of Khushu` is to perform prayer in a tranquil and unhurried manner, when prostrating and bowing, between the two prostrations, and after bowing when standing up again. It is to have complete focus of mind and humility.

There are no reports confirming the incident of `Umar ibn Al-Khattab praying in a church at the time of the conquest of Bayt Al-Maqdis.