What does it mean to sleep? - Psalm 4:9
(ט) בְּשָׁל֣וֹם יַחְדָּו֮ אֶשְׁכְּבָ֪ה וְאִ֫ישָׁ֥ן כִּֽי־אַתָּ֣ה יְהוָ֣ה לְבָדָ֑ד לָ֝בֶ֗טַח תּוֹשִׁיבֵֽנִי׃
(9) Safe and sound, I lie down and sleep, for You alone, O LORD, keep me secure.
(א) בְּרֵאשִׁ֖ית בָּרָ֣א אֱלֹהִ֑ים אֵ֥ת הַשָּׁמַ֖יִם וְאֵ֥ת הָאָֽרֶץ׃
(1) When God began to create heaven and earth—

Psalm 4:9 ,

"In peace and in harmony

I will lie down and sleep,

For You, Lord, will make me

to dwell securely."

What does it mean to sleep?”

According to the Kabbala, Sleep has been compared to the 2,000 year exile, since during sleep, as during the exile, we are not able to see Godliness in the world. Light is hidden from our eyes.

According to recent scientific discoveries, the reticular activating system, in the brain, is responsible for the transition from sleep to wakefulness. Still, it remains a mystery: what sleep is and why we need to sleep.

Insight may be derived from the prayer recited upon awakening, the “Modei Ani” prayer, which expresses thankfulness to God who has returned my soul to me. The soul during sleep has loosened its bonds with the body. It is free to dwell in higher realms.”

Sleep is miraculous. It was in a dream state that the ladder was revealed to Jacob. It was from a dream state that Ezekiel wrote of his visions. From a spiritual point of view, sleep is a time of connection to the Creator of the World.

The first sentence in the Torah states "In the beginning, God creates the heavens and the earth." According to the Baal Shem Tov, this teaches that God creates the world continually, moment by moment. In this way we are enabled to dwell securely in the moment to moment creation of the miraculous world we live in.

When we make the transition from what we see and hear with our physical senses to the mysterious state of sleep, as we ‘fall into sleep’ each evening, we are journeying beyond our understanding. Yet with the awareness that God hears and answers my prayers and continually creates the worlds for my body and my soul to dwell; there, as the psalm conveys, like a comfortable pillow

"I will lie down and sleep

in peace and in harmony.”

(excerpt from "Software for the Soul: Psalms for Everyone - discovering the inner meanings" Click Here for the link.)