Is the one offering the sacrifice liable if its meat spoils?
Praise be to Allah, and prayers and peace be upon our Master the Messenger of Allah.
If the meat (of the sacrifice) spoils due to the negligence of the one offering the sacrifice in preserving it, or due to improper storage, then he is liable to compensate for the portion due to the poor (which is estimated as half a kilogram of meat). If the sacrifice was a vowed (mandatory) one, then he is liable for all of it.
However, if he was not negligent, then there is no liability upon him, because its ruling is the ruling of a trust (like an item left in someone's care). And Allah Almighty knows best.
Is it permissible for a sick person to pray while sitting on a chair?
All perfect praise be to Allah, The Lord of the Worlds It is permissible for a sick person, who is unable to stand up, to offer prayer while sitting on a chair. If he/she was unable to prostrate while on the chair, the he/she should pray while sitting on the ground, but if he/she was neither able to bow (Roku),nor to prostrate, then he can do them while sitting on the chair. And Allah Knows Best.
If a father stops his daughter from getting married, is it permissible for her to conclude the marriage contract herself?
It is permissible for the father to stop his daughter from getting married if there was a lawful reason for that, and she isn`t allowed to conclude the marriage contract without her guardian. However, if her father denied her right in getting married for an unlawful reason, then she should go to court.
Is it permissible to offer an Udhiyah on behalf of the deceased?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
Offering a sacrifice (Udhiyah) on behalf of the deceased is permissible. This is the position of the Hanbalis [Kashshaf al-Qina’ by al-Bahuti (Vol.6/P.428)], and it was held by al-Abbadi of the Shafi’is [Bidayat al-Muhtaj by Ibn Qadi Shuhbah (Vol.4/P.358)]; it is also narrated from some Maliki and Hanafi scholars.
Abu Dawud included a chapter in his Sunan titled "Chapter: Offering the Sacrifice on Behalf of the Deceased," in which he narrated from Hanash, who said: "I saw Ali (may Allah be pleased with him) sacrificing two rams. I asked him, 'What is this?' He replied, 'The Messenger of Allah (peace be upon him) enjoined me to sacrifice on his behalf, so I am sacrificing on his behalf.'"
Abu Dawud also narrated from Jabir (may Allah be pleased with him) that the Prophet (peace be upon him) said: "O Allah, this is from You and for You, on behalf of Muhammad and his Ummah; in the name of Allah, and Allah is the Greatest," then he slaughtered it. It is well known that among the Ummah of Muhammad (peace be upon him) are those who have passed away, yet he (peace be upon him) dedicated it to his entire Ummah.
Furthermore, multiple Sharia texts have consistently indicated that the rewards of righteous deeds reach the deceased. This includes the permissibility of fasting on behalf of the deceased if they died owing fasts, as well as the permissibility of performing Hajj on their behalf, both of which are established in authentic Hadiths. Since the rewards for fasting—a physical act of worship—and Hajj—a physical and financial act of worship—reach the deceased, then the sacrifice (Udhiyah) is even more likely to reach them.
Moreover, the scholars have reached a consensus (Ijma') that the rewards of charities reach the deceased, and the Udhiyah is a form of charity and falls under its general category. Based on all of this, we hold the view that offering a sacrifice on behalf of the deceased is permissible. And Allah the Almighty knows best.
