Does using a respiratory device (oxygen) affect the validity of fasting?
Using an oxygen device does not affect the validity of fasting because oxygen is a gas with no physical substance.
However, if medicinal substances with physical particles are added to the oxygen, its use would break the fast, as it enters the body cavity through a natural passage.
What is the ruling on performing voluntary (nafl) prayer during the time of istiwā' (the sun's zenith) on the day of Jumu‘ah (Friday), and is this ruling specific to someone who has come to the mosque to perform the Jumu‘ah prayer?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
It is permissible to perform voluntary (nafl) prayer during the time of istiwā' (the sun's zenith, i.e., its highest point before noon) on the day of Jumu‘ah (Friday) — whether for someone who is attending the Friday prayer or someone who is not, and whether they are among the people obligated to attend it or not.
It is stated in Mughnī al-Muḥtāj (Vol.1/P.310): "The more correct position (al-aṣaḥḥ) is that prayer is permissible during this time without restriction — regardless of whether the person will be attending the Jumu‘ah prayer or not." And Allah, the Exalted, knows best.
What does (Whoever fasts Ramadan with faith and seeking reward) mean?
This phrase is part of a hadith in which the Prophet ﷺ said:
"Whoever fasts Ramadan with faith and seeks his reward from Allah, their past sins will be forgiven." [Agreed upon]
The meaning is:
● They fast Ramadan with firm belief that Allah has made it obligatory.
● They fast out of obedience to Allah, knowing they will meet Him.
● They hope for reward from Allah and fast purely out of their faith while seeking His reward.
Is it permissible to sleep before the time of the Fajr prayer begins, with the intention of waking up shortly afterward?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is permissible for a Muslim to sleep before the time of the Fajr prayer begins, intending to wake up and perform the prayer, by setting an alarm or asking someone to wake him. What is to be avoided is that a person sleeps while he predominantly assumes that he will not wake up for the prayer.
If he does not wake up until the time of the prayer has ended, he must make it up. It is recommended that he hasten to make it up as soon as he wakes, and likewise recommended that he make up its sunnah along with it.
It is stated in al-Majmūʿ by Shaykh al-Islām Imam al-Nawawī (may Allah have mercy on him): “Whoever was obliged to pray and did not pray until the time passed must make it up, because of the saying of the Prophet (peace and blessings be upon him): ‘Whoever sleeps through a prayer or forgets it, let him pray it when he remembers it.’ It is recommended that he make it up immediately, because of the ḥadīth we have mentioned. If he delays it, that is permissible, because it is reported that the Prophet (peace and blessings be upon him) missed the Fajr prayer and did not pray it until he had left the valley. Had it been required immediately, he would not have delayed it. Abū Is-ḥāq said: If he left it without a valid Sharia excuse, he must make it up immediately, because he was negligent in delaying it.”
It is therefore the duty of every Muslim to keep the prayer in its proper time, seeking help from Allah the Exalted and striving against the self to do so. And Allah Almighty knows best.