Meir Ibn Gabbai (1480-ca. 1540)

The prescribed "time" for scholars [to engage in marital intercourse] is on Sabbath nights. Our Sages expounded on this matter... "That brings forth its fruit in its season" [Ps. 1:3.] . . ..

This refers to the time for the scholar [to perform his marital duty]: on each Sabbath night.
According to the path of truth this is [mandated] because the "Garden is locked" [Cant. 4:12] during the six days of the week, as it is said:
"The gate of the inner court that faces the east shall be closed on the six working days; but on the Sabbath day and on the day of the new moon it shall be opened." [Ezek. 46:1]

For the six days of Creation are garbed in the Profane Days, [those impure forces] that
dwell outside the encampment.
Therefore, during the week there should be no coupling, for the man is not in his house.

However, on the day of the Throne, the mystery of the Seventh Day, the Sabbath, unites with His mate, because at that time, the Profane Days have passed away, the days of impurity and separation are gone, and the wife is permitted to her husband. This is [truly] a veiled mystery.
And so, "when a righteous man couples with his wife during the week, the child who comes forth [from that union] is one of whom it is said: Zaddiq ve-ra' lo, a righteous person who is in adversity." For the child is conceived at a time when the Evil Days reign and [the father] has made the sacred profane. But on Shabbat "the gate of the inner court" is open so as to receive the souls which She distributes to Her children. Since this is the moment of coupling above, the sages engage in marital intercourse [at this time]. Of them it is said: "These are words of the Lord: Concerning the eunuchs that keep my Sabbaths . . ." [Isa. 56:4]

'Eunuchs' refers to those scholars who abstain from sex during the week.

For the rest of the people may engage in marital intercourse daily from midnight onwards, but the scholars arise at (midnight] to immerse themselves in Torah study.

They proceed in this fashion until Sabbath night, which is their (appointed] time [for intercourse].
For then they are crowned in the mystery of the additional soul which wafts downs from its supernal source onto the Final Light [Shekhinah] bestowing upon it eternal rest.

From there, "the soul descends and bathes in the spices of the Garden of Eden" [continuing its descent until] it rests upon those worthy sages and righteous persons"'asher yiSHMeRu-who keep-my Sabbaths." (Isa. 56:4] (The root SHMR, here, is used] as in the verse, "His father SHaMaR, kept the matter in his heart" [Gen. 37:11 ], [that is, he waited].
They [eagerly] await the arrival of Shabbat and prepare for the [moment of] celestial coupling. They choose [to have sexual relations] when it is the desire of their Creator- during the time of celestial coupling, the union of the Bride with Her Beloved-and avoid [marital
relations] during the profane working days. Rather, the scholar must "strengthen His covenant" and power, so that the Holy Essence may spread throughout the world by means of a holy seed. But this "seed of peace and truth" is not of the essence of the Weekday.

It is through (this proper coupling] that Israel is called "children to the Lord" [ff. Dt. 14:1], children of the living God.

And it is written: "Yet I had planted you as a noble vine, altogether a seed of truth." [Jer. 2:21] The Holy One looks upon these children when Israel is amidst travail and has mercy upon them. Of the sages it is said: "Unto them will I give in My house [and within My walls a portion and a memorial better than sons and daughters; I will give them an everlasting memorial that shall not be cut off]." (lsa. 56:5]

What is meant by "in My house"?

As it is said (of Moses]: "He is trusted in all My house." (Num. 12:7]
And "within Your walls?"

As it is said: "Upon your walls, O Jerusalem . . .," the mystery of the celestial Jerusalem [Malkhut.]

"A portion and a memorial:"

This signifies that they will bring forth holy souls from this (celestial] sphere and this "portion," in its fullness and wholeness, "is full of sons and daughters."

"I will give him an everlasting memorial:"

This refers to the one who fathoms the mystery [of coupling] and knows how to concentrate on it with the proper intention.
And since the true sages who are called the true scholars know these awesome mysteries, they abstain from sex and immerse themselves in Torah during the week. But on Sabbath night they diligently [engage in marital intercourse] and parallel the celestial coupling.

Of these men it is said: "He said to me: 'You are My servant, Israel, in whom I will be glorified.' " [Is. 49:3]

(Sod ha-Shabbat, from the Tola'at Ya'aqov of R. Meir ibn Gabbai translated by E. Ginsburg)