Wa `alaykum as-salamu wa rahmatullahi wa barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
The Messenger of Allah (peace and blessings be upon him) said,
“Five practices are of the characteristics of al-fitrah (natural disposition): circumcision, shaving the pubic region, clipping the nails, plucking the underarm hair, and trimming the moustache.” [Al-Bukhari and Muslim]
The majority of Muslim scholars hold the opinion that it is obligatory on Muslim males to get circumcised. Imam Abu Hanifah maintains that it is only recommendable.
The opinion of the majority is more preponderant. A Quranic injunction dictates,
“We have revealed to you, [O Prophet,] that you shall follow the sacred way of Abraham, the [purely] upright.” [16:123]
When circumcision was prescribed for Prophet Abraham (peace be upon him), he circumcised himself, though he was 80 years old [Al-Bukhari].
Accordingly, a Muslim male who is able to get circumcised but neglects it commits a sin by neglecting such an obligation. The circumcision surgery has become very simple and many adult Muslim converts have gone through it for the sake of fulfilling this obligation.
Observing personal hygiene does not relieve one of the obligation, as it is not a matter of personal preference. The very essence of Islam is to submit oneself to the religion’s injunctions and teachings.
Almighty Allah says what means
“Thus it is not ever [befitting] for a believing man or a believing woman, when Allah and His Messenger have decreed a matter, to have for themselves a [contrary] choice in their affairs. For whoever disobeys Allah and His Messenger has truly strayed into clear misguidance.” [33:36]