When does the time for Udhiyah begin?
In the Name of Allah, and may peace and blessings be upon our Master, the Messenger of Allah.
The permissible timeframe for Udhiyah (sacrificial offering) begins on the day of Eid al-Adha—the 10th of Dhul-Hijjah—once the sun has risen and a period of time sufficient to perform two brief prayer units (Rak'ahs) and two short sermons (Khutbahs) has passed. This window remains open until the sun sets on the final day of Tashreeq, which is the 13th of Dhul-Hijjah.
Our Master, the Messenger of Allah (peace and blessings be upon him), said: "Every valley of Mina is a place of sacrifice, and slaughtering may be done throughout all the days of Tashreeq." (Narrated by Al-Bayhaqi and Ibn Hibban)
The days of Tashreeq refer to the 11th, 12th, and 13th of Dhul-Hijjah.
The most virtuous time to perform the sacrifice is immediately after concluding the Eid prayer, based on the statement of the Prophet (peace and blessings be upon him): "The first thing we do on this day of ours is to pray, then we return and offer our sacrifice. Whoever does that has acted in accordance with our Sunnah (tradition), and whoever slaughters before that, it is merely meat he has provided for his family; it has nothing to do with the ritual sacrifice." (Reported by Al-Bukhari and Muslim)
What is meant here is an estimation of time rather than the actual performance of the prayer itself, as our Master, the Messenger of Allah (peace and blessings be upon him), used to offer the Eid al-Adha prayer immediately after sunrise.
The sacrifice is valid if performed at any time during these designated days, whether by day or by night, though slaughtering at night is considered disliked (Makruh). And Allah the Almighty Knows Best.
Does buying meat equivalent to the weight of a slaughtered animal and distributing it avail for an udhiyah?
Praise be to Allah, and prayers and peace be upon our Master the Messenger of Allah.
That does not avail for the sacrifice (uḍḥiyyah), because the sacrifice necessarily requires slaughtering an animal from the category of anʿām (camels, cattle, and sheep/goats) within a specified time.
Rather, that is considered a form of charity (ṣadaqah) for which one is rewarded, but not an udhiyah. And Allah Almighty knows best.
What is the ruling on a woman who gets her menstrual period while fasting?
If a woman gets her menstrual period while fasting, her fast (of that day) becomes invalid, and she must make up for the missed days after Ramadan. Allah has granted ease to women in this situation, and she will be rewarded for not fasting because she is following Allah’s command.
What is the ruling on performing the Istikhara prayer after the Witr paryer?
Praise be to Allah, and peace and blessings be upon our Master, the Messenger of Allah.
The Istikhara prayer (Prayer for seeking guidance) is a Sunnah. It consists of two units (rak’ahs) performed outside of the obligatory prayers, after which the person supplicates with the traditionally narrated du’a. It is permissible to perform it before or after the Witr prayer, as the Istikhara prayer is recommended at all times except during the disliked times—the periods in which prayer is prohibited. This is because its specific reason (the Istikhara and supplication) occurs after the prayer itself, and any prayer with a subsequent reason is not permitted during the prohibited times. It should be noted that the two rak’ahs of Istikhara are not fulfilled by performing only one rak’ah, nor by a prostration of recitation (Sajdat al-Tilawah), nor by a funeral prayer (Janazah). And Allah the Exalted knows best.