All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
As for working in the bank referred to, if its activities, as mentioned, are to give license to the usurious banks, regulate their activities, and set the minimum limit of usury falsely called interest, we see that it is impermissible to work in that bank, due to its unlawful activities, and there is no difference between it and all the other usurious commercial banks, so long as it regulates their activities, sets for them the allowable limit of usury, and gives them license. It is the central bank which gives loans to the commercial banks on an interest basis, so it is their last refuge when they need cash money. To work in that bank is to co-operate in sin and aggression, given that Allaah The Almighty Said (what means): {And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allaah; indeed, Allaah is severe in penalty.}[Quran 5:2] Therefore, it is impermissible to work in it except for him who is forced by necessity, who has not found any other work after a relentless search, and at the same time, fears subjecting himself to death should he leave work in it: it is permissible for such a person to work in that bank, due to the statement of Allaah The Almighty (which means):
· {He has explained in detail to you what He has forbidden you, excepting that to which you are compelled.}[Quran 6:119]
· {But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit], there is no sin upon him. Indeed, Allaah is Forgiving and Merciful.}[Quran 2:173]
As for rinsing the mouth, you should not leave it under pretext of fear of invalidating fast, since, in our view, this is a sort of going to false extremes in religion. According to many scholars of Fiqh, rinsing the mouth is one of the obligatory duties of Wudoo’, and this is the opinion of the Hanbali school of Fiqh. For further information, see Fatwa 84841.
However, the fasting person is forbidden, under Sharee‘ah, to exaggerate in rinsing, not forbidden to rinse his mouth at all. Shaykh Al-Islam Ibn Taymiyyah said: “As for rinsing the mouth and snuffing water into nostrils to clean the nose (during Wudoo’), they are permissible for the fasting person, according to the agreement of scholars. The Prophet, sallallaahu ‘alayhi wa sallam, and the Companions used to rinse their mouths and snuff water into their nostrils while fasting. But he, sallallaahu ‘alayhi wa sallam, said to Laqeet ibn Sabirah : "And exaggerate in snuffing water into your nostrils to clean your nose, unless you are fasting." He thus forbade him from exaggeration and not from the mere snuffing water into the nostrils."
On the other hand, whoever rinses his mouth or snuffs water into his nostrils during Wudoo’ and some water runs into his throat unintentionally and without exaggeration, nothing is due on him, and his fast does not become invalid, according to the sound opinion of the scholars of Fiqh.
Besides, the scholars of Fiqh state that whoever rinses his mouth with water and then swallows his saliva, nothing is due on him, provided that the taste of water disappears and the saliva becomes pure.
So, we advise the questioner to turn away from these doubts, and to rinse his mouth without exaggeration, and devote himself to his prayer, paying no attention to anything afterwards.