Likutei Moharan 17:7/ליקוטי מוהר"ן י״ז:ז׳

17. And know! there are times when the evil sees that the good pining, drawing itself and desiring to return to its place. Then they overpower the good even more and bring it into an even greater concealment—into the inner recesses of their thought. In other words, they start to think thoughts about this good, and by doing so they bring the good into an even greater concealment and obscurity in the inner recesses of their thought.

2As a result, the good then emerges through the offspring which they <these gentiles> bear. <This is because> the good is hidden and concealed in the inner recesses of their thought and mind, from where offspring issue. Therefore, the good emerges in the seed [that produces] their offspring, and the evil of the offspring is then incapable of overpowering the good which they have within them. And so the good emerges through the offspring, resulting in converts. <This is what our sages said (Gittin 57b), “The grandchildren of Sancheriv (Sennacherib) studied Torah.” The Talmud also mentions other wicked people, [pointing out] that specifically their offspring became converts, as explained.>

3And this corresponds to (Psalms 87:6), “God will count, when He inscribes the nations; ‘This one was born there, Selah.’” “Inscribes” is synonymous with the good which emerges through the concept of writing, as above. And this is: “This one was born there, Selah.” The good has become encompassed in the offspring and emerges through them. Thus Rashi explains: This one was born there—“these are the Jews who have become assimilated among the gentiles”; namely, the concept of the good/the parts of the Jewish souls, which they hold captive.

4And this is synonymous with, “He [the Jewish nation] does not lie down until he eats his teref (prey).” This is the perfection of the altar, as explained earlier. “… and drinks the blood of his kill”—which the Targum [Onkelos] translates as: “and the possessions of the nations he inherits”—refers to converts, as above. The “NiKhSay (possessions) of the nations” alludes to the good which is NitKaSah (covered over) by the <nations>. They brought it into concealment and obscurity in the inner recesses of their thought. [The good] then emerges through the seed of their offspring, resulting in converts, and through this the altar is perfected.