Likutei Moharan 49:9/ליקוטי מוהר"ן מ״ט:ט׳

19. Now this is the reason the bride sends the groom a tallit. For the tzaddik receives his strength through the Jewish people, as in, “He set up a tent in their midst for the sun.”

2This is why they say “ELaH” at a wedding, on account of “she is the OLaH (burnt-offering),” as explained above. This is because joy is in the heart, as it is written (Psalms 4:8), “You put joy in my heart.” This also corresponds to “Who is this that ascends”—”who” olah (ascends) together with “this.”

3And the singing of songs at a wedding is the heh, the dalet and the yod, a simple-twofold-threefold-fourfold song, as explained above. This is also why they cry “Shabbos,” because through this we merit the delight of Shabbat, the Torah of the Ancient One.