Musar for Sotah 33:19

Since in Hebrew the name for man and woman i.e. איש ואשה each contain one of these two letters of the Ineffable Name, the י-ה, and the tribes of Israel are known as שבטי י-ה (Psalms 122,4), we can understand that man's duty, i.e. the duty of the אדם התחתון on earth, is to parallel G–d's activities. This means that man and woman are obliged to procreate, "in their image," a son and a daughter just as G–d created in His image a human being comprising male and female components. From the above it follows that when man and woman and son and daughter procreate, they perform the essential (סוד) function assigned to them by the Ineffable Name. When they do that they qualify for the appellation אדם, meaning that they do on earth, i.e. אדמה, something akin to what G–d has done in the Heavens. It is interesting that when you spell the Ineffable Name in words instead of in letters, i.e. 6=יוד-20, הא-6, ואו-13. הא, this adds up to the numerical value of the word 45=אדם. We have already pointed out that man is not called אדם except in conjunction with his mate, his wife. It is known that woman is the מלוי of man, i.e. complements him through her pregnancy. [The process of procreation for man would be impossible without this. Ed.] The alternate name for woman, i.e. 19= חוה. When you consider that the difference between the spelling of the Ineffable Name in letters rather than in words is 19, [45 instead of 26] this demonstrates that G–d's name too is made up of a masculine element and a מלוי, a feminine element. As a unit then, man and woman are called אדם.

This מרכבה is what we described as the ineffable four-lettered name of G–d which comprises both the elements of אב and אם, as well as the elements בן ובת. Since in the mystical realm of תפארת and מלכות the whole concept of-בנין comprising the "two faced" man-is included (compare page 12), we can understand why in terms of הלכה, Jewish religious law, one has not fulfilled one's duty until one has sired both a son and a daughter (in order to reflect this "two faced" original man). In our "lower" world the "two faced" aspect of original man has been replaced by two sexes of separate bodies. By siring both a son and a daughter, the parents have duplicated — to the extent they are able — the basis of this world's structure which is rooted in the emanations of תפארת and מלכות. The result of such a union of איש ואשה, whose names contain one half of the Ineffable Name, i.e. י-ה, is דעת.