Likutei Moharan 112:2/ליקוטי מוהר"ן קי״ב:ב׳

12. Now behold, <Rambam, of blessed memory, writes> that there are three worlds: the angelic world, the terrestrial and the material. The Holy One brings to life and sustains them all with His will. And the person who merits to the truth—God is his light, as it were—sustains the world and provides an influx of bounty to all the three worlds.

2This is what is written: Make a light for the teivah (ark)—That is, speak teivot (words) and> expressions of truth which illuminate. And on this Rashi explains:

3some say a precious jewel, and some say a window—This is as we said, there are two levels. The person who is on the level of real truth illuminates on his own. Thus, “some say” words of truth—these are “a precious jewel” that illuminates from itself. “And some say”—these are words of truth though not of the aforementioned level. They are “a window,” because another person can shine into him as into a window.

4For this is the difference between a precious jewel and a window. A precious jewel illuminates from itself. But a window does not illuminate from itself, although something else, like the sun or something similar, can shine into it.

5And this is: and to an amah (cubit)—Speech is called amah, as AMaH is an acrostic for Aish (fire) Mayim (water), from which speech is comprised, and the Heh refers to the five phonetic families. Thus, “to an amah”—you should speak words which…

6teKhaLenaH (finish it) up above—This is from the connotation of (Psalms 84:3), “My soul KaLtaH (is consumed).” They should be yearned for “Above”; they should be words of truth which illuminate.

7And then: and the opening of the ark put b’ tzidah (in its side)—“TZiDah” is from the connotation of (Genesis 25:28), “[Esav] was a TZayiD (trapper) with his mouth.” This alludes to the evil inclination and the Other Side.

8The meaning is: You should merit to make an opening in the Other Side and the darkness which surrounds on every side. In other words, you should take care to make an opening aimed directly in “its side”—i.e., over and against the Other Side which is called “tzidah .” However strongly the tzidah /the Other Side attacks, to that same degree, directly aimed, must you make “the opening in the teivah”—i.e., the words of truth, as mentioned above. Understand this well.