It is narrated from Ibn Shihab Zuhri (may Allah have mercy on him), he says: When a person would become Muslim, he would be ordered to undergo circumcision, even if he was of advanced age.
Hadith Referenceالادب المفرد / كتاب الختان / 1252
Hadith Gradingالألبانی:صحيح الإسناد موقوفًا أو مقطوعًا
Hadith Takhrij«صحيح الإسناد موقوفًا أو مقطوعًا»
Explanation & Benefits
Shaykh Maulana Usman Muneeb
Benefits and Issues: From this it is understood that in the early generations, new Muslims were ordered to undergo circumcision (khitan), therefore the objection of Hasan al-Basri rahimahullah is not relevant.
Source: Fadlullah al-Ahad: Urdu Commentary on al-Adab al-Mufrad, Page: 1252