Ruling on Letting the Fingernails Grow Long

Q: It is observed that some of the worshippers have fingernails that have grown long and become filled with dirt. Does this agree with the religion? And is their ablution valid?

A: The fingernails must be attended to before forty nights have passed, because the Messenger of Allah (peace and blessings be upon him) set a time limit for the people regarding cutting the fingernails, shaving the pubic hair, plucking the armpit hair, and trimming the mustache: that none of this should be left for more than forty nights. This is what is established from the Messenger of Allah (peace and blessings be upon him).
Anas (may Allah be pleased with him) said, and he was the servant of the Messenger of Allah (peace and blessings be upon him): It was narrated by Imam Muslim in the Sahih, and by Imam Ahmad, al-Nasa'i, and a group of others, in the wording: .
It is obligatory for women and men to observe this matter, so that they do not leave the fingernails, the mustache, the pubic hair—which is the hair—and the armpits for more than forty nights. The ablution is valid, and it is not invalidated by the dirt that may be under the fingernail, because it is slight and is excused.