An-Nawāwī, may Allāh have mercy upon him said in his Majmū’:
(Subsection) Our ashāb said: the time in which the khitān becomes obligatory is after bulūgh (legal puberty). However, it is mustahab (encouraged) for the walī to carry out khitān for the young (śaghīr) in his infancy (śighar) since he is most gentle (rafīq) with him. The author of al-Hāwī, the authors of al-Mustażhiri and al-Bayān, as well as others said:
It is mustahab that he performs the khitān on the seventh day due to a khabar (narration) with regard to this, unless the child is weak whereby he is unable to bear it. He thus delay it until he is able to bear it.
The authors of al-Hāwi and al-Mustażhirī said:
Is the day of wilādah (birth) counted as one of the seven days? With regard to this, there are two wajhs (opinions of the aśhāb). Abū ‘Alī Bin Abū Hurairah said: It is counted. The majority said: It is not counted. The khitān is thus performed on the child on the seventh day after the day of wilādah.
The author of al-Mustażhirī mentioned this in the chapter of Ta’zīr.
The author of al-Hāwī said:
If one performs khitān on him before the seventh day, it is offensive (makrūh).
He further said:
With regard to this, it is the same for the ghulām and the jāriyah.
He then said:
If he delays till after the seventh day, then it is mustahab to perform the khitān on the fortieth day. If he delays it, then it is mustahab in the seventh year.
Note that this, which we mentioned pertaining to the permissibility of one’s khitān during infancy – whereby it is not wajib but mustahab – , is in fact the maźhab (relied upon position) which is śahīh and masyhūr as affirmed by the jumhūr. In this issue is a wajh (opinion of aśhab) that one’s khitān is wājib (legally obligatory) upon the wālī during infancy because it is from his maslaĥahs (means of good for the child), and thus it is obligatory. The author of al-Bayān transmitted it from a hikāyah (transmission) of al-Qādhī Abū Futūĥ from as-Śaidalānī and Abū Sulaiman who said:
The rest of our aśhāb said: It is not wājib.
The third wajh is that his khitān is ĥarām before 10 years old. This is because he is hurting him beyond the pain caused by dharb (hitting), and one should not hit due to prayers except after ten years. This wajh is transmitted by a group amongst them al-Qādhī Husain in his Ta’līq. Al-Baghāwī indicated this at the beginning of his book of śalah. This view is however of no weight and is at a level similar to mukhālif lilijmā’ (inconsistency with consensus).
Imam an-Nawāwi, may Allah have mercy on him then said:
(Subsection) On the maźhab of the ‘ulamā’ with regards to the time of khitān.
We had previously mentioned that our aśhāb considered it mustahab on the seventh day after the day of wilādah. Ibnu al-Munźir said in the book of khitān, from his book al-Asyrāf. This could be found in the last section of Uđhiyah, which is the last part on Haj. He said:
It is narrated from Abū Ja’far from Fāţimah that she made khitān of her son on the seventh day.
He then said
al-Hasan al-Baśrī and Mālik considered it offensive (makrūh) to carry out khitān on the seventh day for mukhālafah (avoidance of imitation) with the Jews. Mālik said: By and large, I see that the carrying out of khitān in our city when the child shed his milk teeth. Ahmad Bin Hanbal said: I did not heard with regard to that from anyone. Al-Laith Bin Sa’d said: Khitān is carried out between seven and ten.
He further said:
It is narrated from Makhūl or others that Ibrahim al-Khalīl, Salutations of Allāh and His Peace upon him, carried out khitān on his son Ishāq on the seventh day and Ismā’īl on the seventeenth year.
Ibnu al-Munźir said after narrating this hikāyah (transmission) in it’s entirety:
There is no prohibition concerning khitān that is thābit (established), neither a hadd (limit) with regard to it’s time to be referred to, nor a sunnah to be followed. All matters (al-Ashyā’) are upon ibāhah (permissibility). There is no prohibition (hazhr) except by hujjah (proof). We do not know of any hujjah from those that prohibit khitān on the seventh day.
This is the end of the quote from Ibnu al-Munźir.
Allāh knows best.