Exodus 12:48
And when a stranger shall sojourn with you, 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.
Torrey's Topical Textbook—AKJV

Isaiah 56:3-7
Neither let the son of the stranger, that has joined himself to the LORD, speak, saying, The LORD has utterly separated me from his people: neither let the eunuch say, Behold, I am a dry tree.
Torrey's Topical Textbook—AKJV