Exodus 12:43-48 King James Version (KJV)
43 And the Lord said unto Moses and Aaron, This is the ordinance of the passover: There shall no stranger eat thereof:
44 But every man's servant that is bought for money, when thou hast circumcised him, then shall he eat thereof.
45 A foreigner and an hired servant shall not eat thereof.
46 In one house shall it be eaten; thou shalt not carry forth ought of the flesh abroad out of the house; neither shall ye break a bone thereof.
47 All the congregation of Israel shall keep it.
48 And when a stranger shall sojourn with thee, and will keep the passover to the Lord, let all his males be circumcised, and then let him come near and keep it; and he shall be as one that is born in the land: for no uncircumcised person shall eat thereof.