The Definition of Circumcision

Circumcision is both a practice from the Fitrah and something that distinguishes Muslims. In the Two Sahihs it is recorded that Abu Hurairah, said that Allah's Messenger ﷺ said:
"The (acts of the) Fitrah are five: Circumcision, shaving the pubic hair, and cutting the moustache short, clipping the finger-nails, and depleting the hair of the armpits."
So the Prophet began with circumcision, and informed us that it is one of the practices of the Fitrah.

The Shari'ah Definition of Circumcision

Question :

Circumcision is to cut off only the foreskin of the male sexual organ, and not to cut off more than that nor even a part of the private part, as practiced in certain primitive lands. While those that cut off more than the foreskin claim that they are performing circumcision according to Islamic principles, they are in reality performing it according to Shaytan's guidance, in order to torture the person who is being circumcised and in order to go contrary to the Sunnah of the Prophet Muhammad and the Shari'ah of Islam, which teaches the principles of ease, comfort, and preservation of life.

The practice of cutting off more than the foreskin is unlawful for the following:

1) We are taught from the Sunnah to cut off only the foreskin.

2) Cutting off more than the foreskin is both a form of torture and disfigurement. The Prophet prohibited harming animals in such manner or severing any of their limbs. Therefore the prohibition of doing so with humans is even more emphasized.

3) Doing so goes against the principles of gentleness and of doing things well. The Messenger of Allah ﷺ said,
"Indeed, Allah has ordered doing well (performance of good deeds and kind acts) over all things."

4) Cutting off more than what is necessary may lead to a great deal of harm, even death. Allâh Almighty says:
"And do not throw yourselves into destruction."

He ﷺ also said:
"And do not kill yourselves (nor kill one another). Surely, Allah is Most Merciful to you."

This is why many scholars say that it is not compulsory to perform circumcision on an adult if we fear that doing so may harm him.

Finally, in some cultures, males and females gather together to witness a child's circumcision. This is wrong because the private part is exposed, which is unlawful, and also because men and women mix together at such gatherings, which is also unlawful.