Exodus 12:48-49

12:48 “When a foreigner lives with you and wants to observe the Passover to the Lord, all his males must be circumcised, and then he may approach and observe it, and he will be like one who is born in the land – but no uncircumcised person may eat of it. 12:49 The same law will apply to the person who is native-born and to the foreigner who lives among you.”