Likutei Moharan 17:4/ליקוטי מוהר"ן י״ז:ד׳

14. Now, the blemish of the altar is perfected through converts. This is because the only power which all <foreign worship> has, comes from the blemish of the altar. As is written (Malakhi 1:11), “In every place [incense] is burnt and [sacrifice] is offered in My name.” Thus, even though they <worship, nevertheless, they receive> all their power from a blemishing of the parts of the altar. This is why the Holy One said: “burnt and offered in My name.” For <all> their power is from the holy spark of the altar of holiness which fell to there.

2Thus, through the converts, because each one of them rejects his own religion and follows the religion of the Jewish people, idolatry, which results from the parts of the altar being blemished, is subordinated. Then, the <holy> sparks of the altar’s parts return to their place and the altar is perfected.

3This corresponds to (Numbers 23:24), “He [the Jewish nation] does not lie down until he eats his teref (prey) and drinks the blood of his kill.” The Targum [Onkelos] translates this as: “… and he inherits the possessions of the nations.” “Eats his TeReF” is synonymous with perfection of the altar, as alluded to in: The altar was in the portion of a ToReiF, as above. And this is achieved by virtue of, “He inherits the possessions of the nations”—namely, through converts. As our Sages teach (Bava Batra 42a) concerning the estate of a convert: The first one [to take possession] of a [deceased] convert’s belongings has acquired them.