Likutei Moharan 75:10/ליקוטי מוהר"ן ע״ה:י׳

110. All the words of Torah and prayer that we speak are the aspect of raising mayin nukvin, as is known. [Such speech] corresponds to peace, as it is written (Isaiah 57:19), “He will create an expression of the lips, peace.” This is the creation’s primary rectification, as it is written (Morning Liturgy): “Who makes peace and creates everything.” For at the time of Creation worlds fell below {on account of the Shattering of the Vessels, as is known}. The worlds correspond to letters. They were scattered into many sparks. But raising the mayin nukvin of Torah and prayer combines the sparks and letters, and through this a world is made.

2And this is the aspect of peace. Before one restores these sparks and letters into the words of Torah and prayer, they are entirely lacking combination and connection. They are the aspect of shards and conflict, with each spark rising up against the other. But when he inserts them into holy speech, he combines and connects them—this being the aspect of peace. For speaking the holy words of Torah and prayer raises the mayin nukvin, which makes peace, as explained above. This rectifies and renews all the fallen worlds, and it is considered as if he has created them anew.

3This is as our Sages, of blessed memory, taught: “and to declare unto Zion: You are ami (My people)” (Isaiah 51:16)—do not read ami, but imi (“with Me”), as My partner. Just as I make heaven and earth through My word, so do you (Zohar, Introduction, p.4b-5a). He does indeed create heaven and earth with words of Torah and prayer, for he continually renews and rectifies the fallen worlds, as explained above.

4This is also the meaning of “I will set peace in the earth” (Leviticus 26:6)—for the sparks ascend from the earthiness to make peace, this being the primary rectification of the creation, as explained above. Therefore, one must speak only holy words and no others, in order to elevate the aforementioned sparks and rectify all the worlds.