Likutei Moharan, Part II 29:1/ליקוטי מוהר"ן·תנינא כ״ט:א׳

1When a halakhic question arises in a person’s home regarding a permitted substance that has become mixed with a prohibited substance, and the permitted is insufficient to offset the prohibited, he is being shown through this that he has blemished some supernal unification. This is because all yichudim (unifications) and unions are the concept of nullifying prohibition.

2This is the meaning of “Who prohibited us betrothed women, and permitted us women who are married [to us]” (The Marriage Service; Ketuvot 7b). It follows, that the prohibited becomes permitted. For initially she is ARUSah (betrothed), and thus was ASURah (prohibited). But afterwards, through marriage, she becomes permitted.

3{“The Lord gathers yechidim (the solitary) into a home; He sets free asirim (those bound) bakosharot (at suitable times)” (Psalms 68:7) .} Therefore, it is said also of the lower union of this world: “The Lord gathers the yechidim into a home”—i.e., unions, as our Sages, of blessed memory, expounded this verse in connection with the marriage union (Sotah 2a). Then, “He sets free ASiRim baKoShaRot”—i.e., the ISsuR (prohibited) is made KoSheR and permitted; the concept of nullifying the prohibition.

4Therefore, when the prohibition is not eliminated and the questionable object is proscribed, it is a sign that he has blemished some supernal yichud, because unification is the concept of nullifying the prohibition.