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 ruling of Islamic Law on supplicating with other than the transmitted (Ma'thur) supplications in prayer?
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah.
It is permissible to supplicate (make du'a) during the prayer for anything from the affairs of religion or worldly life, and the prayer is not invalidated by doing so.
Shaykh al-Islam, the Imam an-Nawawi, may Allah have mercy on him, says: "Our madhhab [i.e., the Shafi'i madhhab] holds that it is permissible for a person to supplicate during it [the prayer] with anything that is permissible to supplicate with outside the prayer, from the affairs of religion or worldly life. He may say: 'O Allah, grant me wholesome sustenance, offspring, a house, and a beautiful young wife' — describing her; or: 'O Allah, free so-and-so from prison,' or 'destroy so-and-so,' and other such things — and none of this invalidates his prayer according to us. And this is also the view of Malik, ath-Thawri, Abu Thawr, and Ishaq." [Al-Majmu', Vol.3/P.454]. And Allah, the Exalted, knows best.
I vowed to give a specific charity if a certain matter came to pass — what is the ruling on giving that charity before the matter is realised?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
Fulfilling a vow (nadhr) is obligatory, in accordance with the word of Allah the Almighty: "And let them fulfil their vows." [Al-Ḥajj/ 29] And the saying of our master the Messenger of Allah ﷺ: "Whoever vows to obey Allah, let him obey Him; and whoever vows to disobey Him, let him not disobey Him." (Reported by al-Bukhārī.)
The Shāfiʿī scholars distinguished between a financial vow (nadhr mālī) and a bodily vow (nadhr badanī). They permitted the fulfilment of a financial vow to be brought forward — before the stipulated condition is met — but did not permit the same for a bodily vow, which may only be fulfilled after the condition has actually been realised.
Shaykh al-Islām Imām Zakariyyā al-Anṣārī, may Allah have mercy upon him, states: "It is permissible to bring forward the fulfilment of a financial vow before the condition stipulated in it is met — such as saying: 'If I am healed, I vow to free a slave' or 'to give such-and-such in charity' — just as it is permissible to pay zakāh in advance. This is unlike a bodily vow, such as fasting." [Asnā al-Maṭālib, vol. 4/P.246]
Imām al-Bājūrī, may Allah have mercy upon him, states: "Like expiation other than fasting, a financial vow — such as saying: 'If Allah heals my sick one, I vow to free a slave for the sake of Allah,' or 'If Allah heals my sick one, I vow to free a slave on the Friday following the recovery' — it is permissible to bring it forward before the recovery in the first case, and before the Friday following the recovery in the second case." [Ḥāshiyat al-Bājūrī ʿalā Sharḥ Ibn Qāsim, Vol.2/P.596] And Allah the Almighty knows best.
What is the ruling on someone who curses the religion or commits an act of disbelief during the day in Ramadan?
Whoever apostatizes (leaves Islam) while fasting, their fast is invalid. Cursing the religion is an act of apostasy (may Allah protect us from it). Such a person must return to Islam by pronouncing the Shahadah (testimony of faith), seek Allah’s forgiveness, refrain from eating and drinking for the rest of the day, and make up for that day’s fast later.
