Likutei Moharan 31:14/ליקוטי מוהר"ן ל״א:י״ד

114. This is what is written, “We will make for you necklaces of gold with points of silver.” For gold corresponds to union, as is written, “gold comes from the north,” and the arousal for union is from the left side, which is north.

2Thus, “We will make for you necklaces of gold.” The letters of the Torah unite and combine through the points of kesef (silver). This is because the union and combination of the letters are by means of the vowel points that are made from the kisufin and longings through which souls—the aspect of vowel points—come into being. A union is made through the yearnings, because as a result of this that he yearns for the thing, a soul is created. And through this that he yearns for the thing, the thing has a reciprocal yearning for him. From this, too, a soul comes into being, and the souls unite. Later on, they come into the aspects of pregnancy and birth.

3This is the meaning of what is written in the Holy Zohar (I, 85b): The desire of the woman produces the soul of a female, the desire of the man produces the soul of a male. This that he yearns, this corresponds to the desire of the woman and it produces a female soul. And this that the object reciprocates with a yearning for him, this corresponds to the desire of the man and produces a male soul. Afterwards, they enter into the aspects of pregnancy and birth, as is recorded there in the Zohar.

4And this is the concept of reincarnation of the souls. For speech, from which souls come forth, is made through the articulation of the letters in the air. The <five articulations of the mouth> strike against each other and articulate letters in the air. Then the [particles of] air strike against each other until they reach the ear of the listener. And through the articulation of the letters in the air, speech, from which the souls come forth, is made. This is because the air is the life-force of all things, and without air it is impossible to live. This corresponds to the soul, and the souls come forth and are reincarnated.