And the Lord spoke to Moses, saying, “Speak to Aaron and his sons, and to all the children of Israel, and say to them: ‘Whatever man of the house of Israel, or of the ger in Israel, who offers his sacrifice for any of his vows or for any of his freewill offerings, which they offer to the Lord as a burnt offering—you shall offer of your own free will a male without blemish from the cattle, from the sheep, or from the goats.
What Does It Say?
Leviticus 22 mostly deals with priestly regulations: who can offer sacrifices, who can partake of the sacrifices, and what can be sacrificed. We see here that ger can also sacrifice freewill offerings (voluntary sacrifices not required by the law) or sacrifices promised to the Lord in a vow.
In other words, the ger are not cut off from the worship of the true God. They are included in the spiritual life of Israel. This "Judaism" (something of a misnomer) is not an exclusive ethnic club. While the nations around Israel are unclean, it is due to their rejection of the law of God, not because of their heritage - otherwise, they could not have approached the altar.
Next: Leviticus 23