Yechezkel taught the disqualification of an uncircumcised man from service in the Beit haMikdash: Zevachim 18b, 22b
Penalty for an arel who works in the Beit haMikdash: Zevachim 23b-24a
An uncircumcised kohen performing kabbalat hadam: Zevachim 15b
Bringing an offering with intent to feed it to an uncircumcised person, or have him perform the service: Zevachim 36a