As the day of Sara and Barry’s wedding draws near, their anticipation and excitement is growing.

Barry is everything Sara ever hoped for in a husband: caring, considerate, intelligent and sensitive. But as the big day approaches, Sara can’t help but feel jittery.

The statistics of broken marriages don’t bode very well. Sara ponders why so many marriages of her friends and acquaintances started off in such joyous bliss, only to end in ugly discord.

“Keep my statutes; do not crossbreed your animals with different species. Do not sow your field with a mixture of different seeds. A garment that contains shaatnez (a forbidden mixture of wool and linen) you shall not wear.” (Leviticus 19:19)

The Torah’s kilayim laws are a series of prohibitions against the intermixing of certain animal species, plant seeds and cloth materials. While the Torah is in favor of unity and harmony, it also respects and guards boundaries.

Beneath the diversity of our world lies the unified purpose of every existent reality: to reveal the singular truth of G‑d, who created us all. On the other hand, we recognize the validity of the categorizations that define our world. Each of us is meant to use our unique characteristics and qualities to make our world a better place.

We do so not by blurring borders or obliterating identities, but by exposing how each of our talents has a place in accomplishing our joint goal.

That is why the crossbreeding of animals or seeds in not permitted: because in the process, each ultimately loses its distinct character and quality. The underlying difference between the two species—how each is meant to serve its creator—has been violated.

However, not all of the kilayim prohibitions apply in all circumstances. The forbidden mixture of wool and linen is permitted—indeed, prescribed—in certain instances, such as in the making of tzitzit, or in the clothes worn by the priests when serving in the Beit Hamikdash (Holy Temple).

This is because, unlike the other combinations of species or seeds, the combination of the two materials in a cloth does not violate the integrity of either ingredient—the wool remains wool and the linen remains linen. What has happened is that these two elements have combined to create a new thing of beauty and utility, while preserving its initial characteristics and qualities.

Still, such a combination is forbidden if the goal is self-serving. Only in the ultimate realization of their purpose—in the service of a mitzvah, the fulfillment of their Creator’s will—can these distinct forces converge in harmony rather than in conflict.

Similarly, the meshing of two species of souls, of man and woman, can occur only when their goal is not a self-serving, narcissistic one.

Husband and wife are two distinct and unique individuals possessing diversified characteristics and attributes, who often originate from divergent backgrounds, cultures or environments, each possessing dissimilar habits, wants and needs.

How can an enduring and productive union occur between such different “planets”? How can these two individuals come to “love each other as oneself,” and live in affectionate unity rather than bitter discord?

Only when each preserves and employs his or her characteristics within the marriage in the service of a higher goal.

This is implied by the Hebrew words ish (man) and ishah (woman). The common letters in each word are the alef and shin, spelling eish, fire. The exclusive letter in each is yud and hei, forming one of the names of G‑d.

When man and woman base their relationship on sincerity and dedication to a higher goal, he contributes his yud and she contributes her hei—and the two work in unison, through their own distinct channels, to bring spirituality into their home.

If, however, each brings his/her personal agenda or egotistical biases into the relationship, he leaving out his yud and she her hei, and what remains is eish, a relationship fraught with fiery destructiveness and strife.1

This is why the first letter of the Torah is the second letter of the Hebrew alphabet—the beit, in the verse Bereishit bara Elokim, “In the beginning, G‑d created . . . ” The first letter, the aleph, cannot be the initial letter of the Torah because its numerical value is one, indicating separation and isolation. In order to convey a blessing, the letter beit, whose numerical value is two, was needed.

For blessing only comes when there is diversity. Only in making room for another—and assisting the other to employ his or her distinct thoughts, dreams, needs and aspirations in the service of a higher goal—can blessing occur.

On the other hand, the Hebrew word for love, ahavah, is numerically equivalent to echad, one. The sum of both words totals 26, the numerical equivalent of G‑d’s quintessential name, the Tetragrammaton.

A couple’s true love expresses a oneness reflective of their quintessential unity. When they draw together in love and appreciation for the individuality of each other, they discover how to use their distinctions in the ultimate realization of their joint purpose.

And only then have the two united to create a loving environment which G‑d can call His home.