My brother works in a conventional bank and gave me one of the gifts distributed to bank employees — what is the ruling on accepting it?
All praise is due to Allah, and peace and blessings be upon our master the Messenger of Allah ﷺ.
There is no objection to accepting such gifts, because the physical gift itself does not carry any inherent prohibition — unlike stolen property. Sin does not transfer or extend to the one who receives the gift, for Allah the Almighty says {what means}: "And no bearer of burdens shall bear the burden of another." [Al-Anʿām/164]
The evidence for this is that the Prophet ﷺ himself ate from the food of the Jews, conducted transactions with them, and purchased from them — and it is well known that their wealth was intermingled with ribā. Similarly, the wealth of conventional ribā-based banks is a mixture of the lawful and the unlawful.
Ibn Ḥajar al-Haytamī, may Allah have mercy upon him, states: "It is not forbidden to transact with one whose wealth is predominantly unlawful, nor to eat from it — as al-Nawawī affirmed in al-Majmūʿ." [Tuḥfat al-Muḥtāj, Vol. 9/P.389] And Allah the Almighty knows best.
What should one who doubts the validity of his ablution and performs it frequently do?
Whoever doubts the validity of his ablution after finishing it, his ablution is valid. This is because the default is the validity of the ablution, and because doubt after finishing an act of worship doesn`t affect its validity. And Allah the Almighty knows best.
What is the ruling on one who performs ablution or the ritual bath while having nail polish?
Nail polish must be removed before ablution or ritual bath so that water reaches what is beneath it, because it is a barrier that prevents water from reaching that area. This is based on the hadith narrated by Ali (may Allah be pleased with him) from the Prophet (peace be upon him): "Whoever leaves a hair's breadth of his body unwashed from major impurity, such and such will be done to him in the Fire." (Reported by al-Bukhari). And Allah the Almighty knows best.
Should a person feel pleased, or have a virtuous vision after offering Istikhara (guidance prayer) in order to do what he/she had offered it for?
The result of the Istikhaarah is not necessarily that a person sees something (in his dream), or feels pleased, but the most important result of the Istikhaarah is whether a person is enabled to do a given matter or not.