It says in the Bible, "Therefore shall a man leave his father and mother, and cleave to his wife, and become one flesh" (Gen. 2:24). What does this mean, "one flesh"?

It could simply mean the body of the child born to a father and mother since, in the conception and birth of a child, man and woman "become one flesh." But then why didn't G‑d just say, "Get together and have children"?

Because what G‑d was talking about was more than physical. Such merging is impossible in the physical world. But husband and wife are more than physical, and marriage is intended to be a divine institution. On a spiritual level, therefore, husband and wife are capable of a unique and wondrous unity. And on that level, "becoming one" refers to intimacy.

Yet if G‑d was trying to tell Adam and Eve that He intended marriage to be intimate, why didn't He say, "Become one heart, one mind, and one soul"? Because becoming one flesh refers to an intimacy even greater than that of being of one heart, one mind, and one soul.

As far as souls are concerned, husband and wife are already two halves of the same soul, reunited at the time of marriage. They don't need to become one because they are one, and have always been since the time of creation.

As far as minds are concerned, to "become of one mind" is not unique to marriage. Friends can be of one mind.

To be of a single heart is also not unique to marriage. When the Children of Israel stood together at Mt. Sinai to receive the commandments, they were gathered there with a single purpose, "like one person with one heart" (Commentary of Rashi on Exod. 19:2).

Being of one flesh is more intimate than being of one soul, one mind, and one heart, because marriage accomplishes what no other relationship can accomplish: man and woman becoming one in the concerns of the flesh.

To fully comprehend the idea of one flesh, we first need to understand the concept of two types of souls. The human being functions on two levels: the immortal G‑dly level, and the mortal natural level.

The immortal soul, which is of G‑d, refers to that part of our personality in which we experience G‑dly feelings and yearnings to be like G‑d, to imitate G‑d's ways even in the physical world. The mortal soul is that part of our personality that can relate to purely earthly needs. When we talk about the concerns of the flesh, we are referring to that state of mind, those characteristics, feelings, and emotions that come from the physical body in which we exist. By sharing the concerns of the flesh, that is, the needs of their mortal souls, husband and wife become one.

When we talk about the needs of the mortal soul, we mean more than physical needs such as eating, sleeping, and reproducing. We also mean the needs of the ego: the need to defend ourselves against insult, the need for recognition, the need to feel significant, the need to be respected, the need to be appreciated, the need to be understood, the need to be secure. All of these are the needs of our human condition: our mortal soul.

We recognize these needs in our children. Every child needs to be nurtured, protected, made to feel secure, defended against insult, recognized, understood, and appreciated. Yet the mature person, the person of virtue, is someone who has managed to transcend these needs, who can overlook an insult, who doesn't need to defend himself constantly, and who would rather give than receive respect.

In our efforts to be more G‑dly, our goal as we mature is to grow away from the needs of the mortal soul toward the needs of the immortal soul. By giving us commandments to follow, G‑d let us know that we can transcend the needs of the body, and likewise the needs of our mortal soul.

There is nothing sacred or absolute about the demands of the mortal soul. For example, although the body needs to eat, G‑d commanded the Jews to fast on Yom Kippur, the Day of Atonement. No one is horrified by the thought of fasting on that occasion.

The same is true with almost every physical need the body has. There are times when we say "no," and times when we are told to say "no." Either way, the message is clear that the needs of the body, of the physical condition, are not absolute.

A fifteen-year-old rabbinic student was once staying for a time in his teacher's home. The teacher, taking the obligation of hospitality seriously, would allow no one to serve the boy but himself. On the first morning, when the student came down for breakfast, the older man said, "Here, have a little of this, and a little more of that. Take more! This is fresh, and this is good," and so forth. The boy ate everything that was placed in front of him.

That evening, walking home from the synagogue together, the teacher said to the boy, "I hope you don't mind my saying this, but a person can't be like an animal, eating food just because it's in front of him. You don't have to eat everything you see. You can control yourself."

"I don't understand. You told me to eat it."

"Yes, I told you to eat it, but who says you had to eat?"

The student thought, "Okay, okay, I get the message." But the next morning, the teacher said to the student, "Here, have a little of this, and a little more of this. And try this; it's homemade."

Walking home that night, he again scolded the boy. "You really need to control your appetite. You can't indulge yourself in everything you want."

After this happened a number of times, the boy said to the older man, "What do you want from me? You're driving me crazy! First you tell me to eat, then you tell me not to eat. Tell me what you want!"

"What do I want? I don't want anything. In the morning, you are my guest. As a host, I can't tell you to control your appetite, not while you are sitting at the table in my kitchen. Then it's my obligation to serve you, which I do.

"But it's not your obligation to eat so much. So, as your teacher, it's my responsibility to train you, and share with you some of my learning."

Ideally, becoming an adult means understanding that we don't need to gratify our every desire, and that it isn't necessary to defend our egos at all costs. We are then more likely to be able to care for someone else's needs, and to defend someone else's ego.

"Now," you might say, "wait a minute. I just finished growing up and it took me twenty years to learn that my ego is not sacred. Now you're telling me that I should take someone else's ego seriously. It seems like going backwards."

It's not going backwards at all. It's a giant step forward. You have felt the need to be appreciated, to be respected, to feel secure; but after twenty years of growth and maturity, you've come to realize that you don't absolutely have to be appreciated or respected or feel secure. Your ego does not at all times have to be gratified.

To yourself, become the boy's teacher, saying, "I don't really need this, and I don't have to have that." Admonish yourself, never others, unless it is your place to teach. Instead, you should treat others as the host treated the boy.

Once you have discovered your own earthy needs and impulses, your ego's desire to be recognized, and the wants of your mortal soul, you are capable of gratifying those very needs in someone else. To those around you, you should say, "Here, this is for you, and this is for you. Let me do this for you, and let me get that for you."

I had a great-uncle who was a wonderful example to me. He was a humble man. The events of his life had humbled him—he had lived through the war, his wife had died at a young age, and he had no children; but he was also humble through personal virtue. He lived alone, and from time to time he came to our house for dinner. He was very gentle, rarely spoke, and never raised his voice. Because we were young, we thought him a little senile.

One day we were sitting at the kitchen table. My mother was standing at the sink, and I asked her to hand me a spoon. This gentle old man turned livid; he became indignant and quite beside himself.

He said, "Banutzin zich mit di mamen?" In other words, why are you using your mother? Sending her on an errand for you?

That was all. Then he was silent once more.

Why was he livid with indignation? He was morally outraged that a child could say to a mother, "Get me this, get me that." A child should get up and get it for himself. Sending a mother was unheard of and unthinkable.

This was a man who never asked for anything. He never asked us to carry packages for him, to come to his apartment, to move furniture, never a request for himself. To his mind, who was he to ask a favor of someone else?

But my mother's honor was a different matter. On someone else's behalf, the man who never spoke for himself would speak out. What he had learned to dismiss in himself he took very seriously in others. Life had taught him its lessons well. (Incidentally, my mother never noticed my indiscretion.)

This is what distinguishes us from the children we once were. Having gotten bigger than our own egos, we can now take someone else's ego seriously. The next step, the logical step, the G‑dly step, is to appreciate someone else, to respect someone else, to make someone else feel secure. And for this we are now qualified.

That's why we wait to be married until we are ready to be married, when we are grown, and able take on the responsibility for another person's mortal soul—having finally mastered our own.

Then we remind ourselves, "The needs of my mortal soul are there so I can understand what another person is feeling, and take care of that person's needs; to take care of my own would be hedonistic. Now that I have felt the need for respect, for appreciation, and for security, I know how to respect, appreciate, and make someone else feel secure."

When we deny the needs of our mortal soul, yet gratify those same needs in someone else, we imitate G‑d. Then we are free to proceed along the lines of spiritual growth. Then we think, feel, and act in a holy manner, in a way that is like G‑d. Just as G‑d is merciful to us, we learn to be merciful to others. Just as G‑d forgives us, we learn to forgive others, and so on.

Where do we really see all of this practiced? In marriage. When does all this really get put into effect? In marriage.

Marriage is the arena in which all we discover on the way to becoming "like G‑d" is put into practice. To be devoted to a relationship means to be devoted to the other person's needs, more so than to your own. It means taking on the other person's needs as though they were yours. In so doing, two people merge into one.

This same oneness occurs in the metaphysical realm. In trying to grasp a G‑dly subject, for example, the mind simultaneously envelops the subject and is itself surrounded by the subject. This double oneness or mutual merging, where each object both surrounds and is surrounded by the other, is a divine occurrence. When husband and wife become one flesh, they bridge the gap between what is physical and what is spiritual, between what is mortal and what is immortal, between what is merely human and what is G‑dly. And they do this on a daily basis, in a way that only two people who are married can do.

In that way, husband and wife are truly capable of a unique and wondrous unity, a double oneness.