What is the ruling on performing dry ablution (tayammum) on a wall or stone?
One of the conditions for tayammum is that it be with pure, clean dust (soil). It is not valid to perform tayammum by striking stones, a wall, sand that has no dust (i.e., that does not produce dust), pebbles alone, or clay, as these are not from the earth or its same category. And Allah the Almighty knows best.
A man led the people in prayer as imam, and at the end of the prayer he performed a prostration of forgetfulness (*sujūd al-sahw*) because he had omitted a short *sūrah* after al-Fātiḥah. What is the ruling on his prayer and that of those praying behind him?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
According to the Shāfiʿī school, it is sunnah to recite a sūrah after al-Fātiḥah in the prayer. One who omits it has a valid prayer, and no prostration of forgetfulness (sujūd al-sahw) is prescribed for omitting it. If someone performs sujūd al-sahw for its omission while knowing the ruling and remembering it, his prayer is invalidated. But one who is ignorant of the ruling, or who did so out of forgetfulness, his prayer is not invalidated, because this is among the matters that are obscure to people, and ignorance of it is not restricted to those who recently entered Islam.
Shaykh al-Islām al-Shams al-Ramlī said in Nihāyat al-Muḥtāj ilā Sharḥ al-Minhāj (Vol.2/p.70): “The remaining sunnahs are not compensated for by prostration, such as the remembrances (adhkār) of bowing and prostration, that is, the opening supplication (duʿāʾ al-iftitāḥ) and the sūrah, in accordance with the base rule, because they are not of the same nature as what has been reported [as compensable]. If one prostrates for any of them deliberately, his prayer is invalidated, unless he is excused due to ignorance. As for the objection raised that the ignorant person does not know that sujūd al-sahw is prescribed, and whoever knows it knows its place, this is refuted by denying such a necessary connection, for the ignorant person may hear only that sujūd al-sahw is prescribed before the salām, and so assume that it applies to every sunnah and is not restricted to its prescribed place.”
This is among the matters that are obscure, in which the mukallaf is excused for ignorance, as stated by al-Shabrāmallisī in his Ḥāshiyah ʿalā Nihāyat al-Muḥtāj (Vol.2/p.70).
However, if the imam prostrates, and the follower (maʾmūm) presumes that his imam’s prostration is for a reason for which one does not prostrate, it is not permissible to follow him in it, so long as the follower knows the ruling.
Accordingly, the prayer of one who did not recite a sūrah after al-Fātiḥah is valid, and sujūd al-sahw is not prescribed for it. Whoever prostrates out of ignorance or forgetfulness, his prayer is valid, because this is among the issues hidden from the general public. But whoever prostrates while knowing the ruling and remembering it, his prayer is invalidated. And Allah Almighty knows best.
Does collecting saliva and swallowing it break the fast?
Swallowing collected saliva does not break the fast, but it is an unnecessary and meaningless act.
What is the semi-circular structure attached to the Holy Kabah?
The semi-circular structure attached to the Holy Kabah is Hijr Al-Kabah (is a low wall originally part of the Kabah) and passing behind it is an obligation while making Tawaf because it is a part of the Holy Kabah. And Allah Knows Best.
