Day Questions

I have given up in life. Is there a supplication that can bring me death?

There is no dua for wishing to die. It is not amongst the characters of a believer to wish to die, nor to ask his Lord for such an issue. Rather, a believer is expected to call Almighty Allah to remove the hardship and decrease its effect on him, as He is All-Merciful.

Can a girl still pray while she has colored nail polish on fingers and/or toes?

Having nail polish is permissible during the prayer if it was applied after wudhu or ghusl. It prevents water from reaching the nail so it invalidates wudhu or ghusl if it was applied before performing any one of them. It can be applied on some of the toes that are not wiped during wudhu.