The imam recited a verse containing a prostration of recitation (*sajdat al-tilāwah*) but did not prostrate. After the imam's *salām*, a follower (*maʾmūm*) performed a prostration of forgetfulness (*sujūd al-sahw*) because the imam had not performed the prostration of recitation. Is it permissible to go against the imam in this way?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
There is no sin on the imam if he omits the prostration of recitation (sujūd al-tilāwah), even deliberately. The maʾmūm (the one following the imam) is obliged to follow the imam in the prayer, so if the imam does not perform the prostration of recitation, it is not permissible for the follower to prostrate, because the imam is appointed only to be followed.
If the follower introduces a prostration after the imam’s salām but before his own salām, in a case where there is no prostration of forgetfulness (sujūd al-sahw), his prayer is invalidated if he knew it to be prohibited. Otherwise, he is excused on account of his ignorance and his prayer is not invalidated.
It is stated in Ḥāshiyat al-Imām al-Jamal ʿalā Fatḥ al-Wahhāb: “His statement: ‘So the omission of the hayʾāt (the non-essential sunnahs of the prayer) is not compensated for by prostration; if one prostrates for any of them deliberately, his prayer is invalidated, unless he is excused due to his ignorance.’”
Since this issue is one that is hidden from the laymen, as it is among the subtleties of knowledge, and the laymen are excused for ignorance of whatever is of such a nature, and their act of obedience is not invalidated because of it, it may be said that the prayer of one who has not acquired knowledge of this issue is not invalidated, with the necessity of learning the rulings remaining. As for after knowing it, the prayer is invalidated. And Allah Almighty knows best.
Is the son of the sister by breastfeeding considered a mahram in Islam, and is it permissible for a woman to go for Hajj with him?
Everything that is prohibited by lineage is also prohibited by breastfeeding. The son of the sister by breastfeeding is considered a mahram, just like the son of the sister by blood, and it is permissible for him to be her mahram for Hajj and Umrah. And Allah Knows Best.
What are the categories of the livestock permissible for Udhiyah?
In the Name of Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
An Udhiyah (sacrificial offering) is only valid if it is selected from Al-An'am (livestock), which includes: camels, cattle, and sheep or goats—whether male or female, and even if castrated. Allah Almighty says {what means}: "And for all religion We have appointed a rite [of sacrifice] that they may mention the name of Allah over what He has provided for them of [sacrificial] livestock." (Al-Hajj/ 34)
In terms of preference, camels are considered the best choice, followed by cattle, then sheep, and finally goats.
A single sheep or goat is valid as a sacrifice on behalf of one person. However, a single camel or cow can be shared by up to seven people. This is based on the narration of Jabir (may Allah be pleased with him), who said: "In the year of Al-Hudaybiyah, we sacrificed along with the Messenger of Allah (peace and blessings be upon him) a camel on behalf of seven people, and a cow on behalf of seven people." (Narrated by Muslim)
(Note: The term "Badanah" used in the original Arabic text specifically refers to a camel in this context). And Allah the Almighty Knows Best.
Is it permissible for a woman to shake hands with her brother-in-law?
It is forbidden for the woman to shake hands with her brother-in-law because he isn`t a Mahram (unmarriageable) of hers.