Moussar sur La Genèse 1:26

Chapter 1 - That it is fitting for a person to resemble his Creator: It is fitting for a person to resemble his Creator and then he will be [configured] in the secret of the Highest Form, [both] in image and likeness. As if he is alike in his body but not in his actions, he betrays the Form; and they will say about him, "A lovely form, but ugly deeds." As behold, the essence of the Highest Image and Likeness is His actions. And what will it benefit him to have the structure of his limbs like the Highest Form, but not resemble his Creator in his actions? Therefore it is fitting that he should [make his actions] resemble the actions of the Crown (Keter), which are the thirteen highest traits of mercy. And they are hinted to in the secret of the verses (Michah 7:18-20), "Who is a power like You; He will again have mercy on us; You shall give truth." If so, it is fitting that these thirteen traits [also] be found in man. And now we will explain these thirteen actions that are fitting to be with him.

The author views the creation of the emanations i.e. אצילות [a collective term used by the author of the book פרדס רמונים for all the ספירות. Ed.], as something akin to a "body." This means that the אין סוף (another word for G–d's Essence) needed to "wrap" itself in a spiritual emanation in order to eventually ennoble man through granting him some of the אור הנעלם. If G–d had not done so, man would not have a chance to get to know anything meaningful about G–d. The need for these emanations arises from the fact that without them the effect of the Revelation would be so overpowering that it would simply shatter us, much as noise at decibels that our ears are not attuned to would shatter our sense of hearing. [I have heard this explained as similar to a high voltage transformer which reduces such voltage in order to protect the electrically operated gadgets that we use in our household. If the voltage would hit our gadgets at full strength it would simply destroy them. Ed.]. When G–d said in Genesis 1,26: "Let Us make man in Our image and in Our likeness," this was a plan to create the most perfect creature, a creature that would effectively be the world, i.e. would be enthroned in this physical world much as G–d Himself is enthroned in the Heavens. The communication between man's soul and that soul's origin to the אדם העליון, [a term for the highest of the emanations], would be unimpeded.

Man's purpose is to perfect his resemblance to the Divine. It follows that even those aspects of his body which are more mundane by nature should be elevated to a level of חולין שנעשו על טהרת הקודש, "profane matters treated as if all the restrictions of sacred matters applied to them." This includes the act of sexual union with his wife. At first glance the very desire to engage in sexual intercourse is demeaning, reflects the dominance of our physiological impulses over our spiritual impulses. This can be overcome when man sanctifies himself prior to engaging in marital relations with his wife. When he does so he not only models himself on the Divine but the children who will be born as a result of such a physical/spiritual union will reflect the דמות ה' in an intensified measure. We have elaborated on this elsewhere as well as on the fact that there are three partners involved in the making of every human being, G–d having said "Let us make man in Our likeness" (Genesis 1,26). [This refers to G–d's participation in the creation of every human being subsequent to the first. I have found this confirmed in ראשית חכמה, שער קדושה, פרק טז, paragraph 56 in the new edition by Rabbi Joseph Chayim Waldman. Ed.] G–d's participation is conditional on the act of marital union being performed under the aegis of the סטרא דקדושה, the sacred side of the emanations.