וכל ערל לא יאכל בו
שמות יב – מח
A person who is uncircumcised may not eat from a Korban Pesach. This includes a person who cannot do a Bris Mila because his brothers have died from their circumcision. While someone who is uncircumcised by choice is also included, he is prohibited to eat also because he is a non-believer.
The Mitzva of eating Matza and Marror are not included. They may eat Matza and Marror.
In the time of the Bais Ha`Mikdash, when there is a Korban Pesach.
In Psachim 96 and in the 8th perek of Yevamos
If one transgresses
One gets Malkos.