Tazria Parashat Yoledet, Chapter 1
1) ("And on the eighth day he shall circumcise the flesh of his foreskin.") I might think either in the daytime or at night; it is, therefore, written "the day" — the day and not the night. This tells me (only) that one circumcised on the eighth day must be circumcised in the daytime. Whence do I derive the same for one who is circumcised on the ninth day or the tenth day or the eleventh day or on any other day? From "and on the day."