(א) בְּרֵאשִׁ֖ית בָּרָ֣א אֱלֹהִ֑ים אֵ֥/ת הַשָּׁמַ֖יִם וְאֵ֥ת הָאָֽרֶץ׃ (ג) וַיֹּ֥אמֶר אֱלֹהִ֖ים יְהִ֣י א֑וֹר...
(1) With beginning Elohim was created (and) the letters (aleph through tav (ET)) and heaven and earth. (3) And Elohim (said) (speaks the world into existence) “Let there be light”...
(טז) צֹ֣הַר ׀ תַּעֲשֶׂ֣ה לַתֵּבָ֗ה...
(16) Make an opening for daylight in the ark ...
(א) צהר. יֵ"אֹ חַלּוֹן וְיֵ"אֹ אֶבֶן טוֹבָה הַמְּאִירָה לָהֶם (ב"ר שם):
(1) צהר A LIGHT — Some say this was a window; others say that it was a precious stone that gave light to them (Genesis Rabbah 31:11).
(א) טו. צהר תעשה לתבה. ריב"ש ע"ה אמר, צהר תעשה לתבה, שתהיה התבה [שאדם מדבר בתורה ובתפלה] מצהיר, כי יש בכל אות עולמות ונשמות ואלהות, ועולים ומתקשרים ומתייחדים זה עם זה, עם אלהות, ואז מתייחדים כל העולמות כאחד ועולים ונעשה שמחה ותענוג גדול עד אין שיעור.
(צוואת הריב"ש ד"ח ע"ב, ובס' אור התורה).
(1) "Make an opening [tzohar] for the ark [teivah]. The Baal Shem Tov, peace be upon him, explained these words in the following way: let the word (teivah) said in Torah or in prayer radiate light (matzhir)! For in every letter there are worlds, souls and divinity, that rise up and interconnect and cleave to one another and to the divine. In this way, all the worlds rise and become as one, and then there is immense joy and immeasurable delight.
The Baal Shem Tov teaches:
When you focus all your intention on the power of the words you may begin to see the sparks of light that shine within them. The sacred letters of your heart are the chambers into which the Divine pours flowing light. The lights within each letter ignite one another, and new lights within and without are born.
The Maggid of Mezeritch teaches:
The purpose of prayer is to uplift the words, to return them to their source above (a recycling). The world was created by the downward flow of letters. Our task is to form those letters into words and lift them up to their source. If you come to know this dual process your words may be joined to the constant ongoing flow of creation - word to word, breath to breath, thought to thought. The Divine spring is ever flowing: make yourself into a channel to receive the waters from above.
Rabbi Pinchas of Koretz teaches:
People think they pray to the Divine One. But this is not the case. For prayer itself is of the essence of Divinity.
Sources:
The Ba'al Shem Tov teaches, Keter Shem Tov, 47b,
The Maggid of Mezeritch teaches, Or Torah, pages 58b-59a
Rabbi Pinchas of Koretz teaches, Imre Pinchas, page 40
"ET" (Genesis 1:1) comprises the entire alphabet, aleph through tav. See parallel to "I am the Alpha and the Omega." Zohar, Pritzker Edition, volume 1, 1:50b note 1325 and in other places.