Tanya Chapter 23, Class 7 (177). ולא עוד אלא… So far Mitzvos are like the Keilim (vessels) of Atzilus and the the Torah is likened to the Ohr (light); here the Alter Rebbe adds that in fact Torah reveals (בגילוי לגמרי בלי הסתר פנים כלל וכלל) the level of Ohr called סובב כל עלמין that is higher than the highest world as the Torah is the blueprint of all the creation. Though this is revealed it doesn’t destroy us as we don’t experience it, so we can actually learn the Torah (and the ones above cannot).
