The shar’i (religious) benefits:
Circumcision is one of the commands concerning beautification enjoined by Allaah, which Allaah has prescribed for His slaves to make them beautiful both outwardly and inwardly (physically and spiritually). It is the perfection of the fitrah (natural state of man) with which He created them, and hence it is the perfection of the haneefiyyah (pure monotheism) of the religion of Ibraaheem (Abraham). The origin of the institution of circumcision as the perfection of haneefiyyah was when Allaah made a covenant with Ibraaheem and promised to make him an imaam (leader) of mankind, and promised him that he would be the father of many people, that prophets and kings would come from his loins and that his descendants would be many. And He told him that between him and his descendants there would be the sign of the covenant, which would be that every newborn male among them would be circumcised, and so the covenant would have this sign on their bodies. Circumcision is a sign of having entered into the religion of Ibraaheem, and this is in accordance with the interpretation of the verse (interpretation of the meaning) –
“[Our Sibghah (religion) is] the Sibghah (religion) of Allaah (Islam) and which Sibghah (religion) can be better than Allaah’s? And we are His worshippers”
[al-Baqarah 2:138] –
as referring to circumcision.
For the haneefs (pure monotheists, i.e., Muslims), circumcision has the same status as baptism does for the worshippers of the cross (i.e., Christians). They purify their children – as they say – when they baptize them in the baptismal water, and they say, now he has become a Christian. Allaah has prescribed for the haneefs their own rite, the symbol of which is circumcision. Allaah says (interpretation of the meaning):
“[Our Sibghah (religion) is] the Sibghah (religion) of Allaah (Islam) and which Sibghah (religion) can be better than Allaah’s? And we are His worshippers”
[al-Baqarah 2:138] –
… So Allaah has made circumcision a symbol of those who belong to Him and to His religion, and who attribute themselves to Him as being utterly enslaved to Him alone…
The point here is that the religion of Allaah is haneefiyyah (pure monotheism) which fills the heart with knowledge and love of Him and sincerity towards Him, and worship of Him alone with no partner or associate, and which marks the body with the characteristics of the fitrah, namely circumcision, removal of the pubic hair, trimming the moustache, cutting the nails, plucking the hair from the armpits, rinsing the mouth, rinsing the nose, using the siwaak (toothbrush made from twigs from a certain tree) and cleaning oneself after elimination of urine or faeces.
So the fitrah of Allaah is manifested in the hearts of the haneefs and on their bodies.
(Tuhfat al-Mawdood bi Ahkaam al-Mawlood by Ibn al-Qayyim, p. 351)
It is not essential for the child to remain as he is when he comes forth from his mother’s womb, if there is something that may be done for him that serves a purpose and is enjoined by the pure religion. Such things include shaving his head after he is born, because that is in his best interests. The Prophet of Islam (peace and blessings of Allaah be upon him) said: “Remove the harm from him.”
The same applies to washing the blood from him and cutting the cord by which he was attached to his mother, and other things which are done to benefit him.
The health benefits:
Dr. Muhammad ‘Ali al-Baar (a member of the Royal College of Surgeons in the UK and a consultant to the Islamic Medicine department of the King Fahd Centre for Medical Research in the King Abdul Aziz University in Jeddah) says in his book al-Khitaan (Circumcision):
“Circumcision of newborn boys (i.e., within the first month of life) brings numerous health benefits, including:
1 – Protection against local infection in the penis, which may result from the presence of the foreskin, causing tightening of the foreskin, which may lead to retention of urine or infections of the glans (tip) of the penis – which require circumcision in order to treat these problems. In chronic cases, the child may be exposed to numerous diseases in the future, the most serious of which is cancer of the penis.