The 3 Shabbat Meals of Atika Kadisha, The Ancient Holy One
Zohar Shemot 88A
Rabbi Shimon said: When a man has completed the three meals on Shabbat, a voice comes forth and proclaims of him: "Then shall you delight yourself in G‑d" (Isaiah 58:14). This is in reference to one [the first] meal (on Friday night), which corresponds to Atika Kadisha, the holiest of all the holy levels.