A person should be happy in the three meals of Shabbat because they represent complete faith. Faith, ‘Emunah’ is the aspect of the Shechina (Zohar Hasulam Pikudei #628). The three meals of Shabbat connect us with the Shechina to the supreme Keter, Atika Kadisha.
Rabbi Shimon says that he never messed three Shabbat meals all his life. Those who have the merit of three meals, ears the complete faith, which is closer connection to the Shechina. The first meal of Shabbat connects to the ‘queen’, which is the Shechina in Malchut because the night is under the control of Malchut.
The second meal at the morning of Shabbat connects to the light of the concealed wisdom from the Atika Kadisha. The morning prayers of Shabbat connect to Zeir Anpin that elevates to Atika Kadisha in the afternoon, the time of the third meal.
The Second meal is called the meal of Atika Kadisha and the third meal is called for the name of Zeir Anpin.
As Zeir Anpin ascend to Atika Kadisha, the ‘forehead’/‘will’ of the Keter is revealed and judgments have no control during Shabbat.
The concealed wisdom (חוכמה סתימאה) is the the third head of Arich Anpin and include within it the other two. It has the light of Atikah Kadisha and is called the Concealed Supreme Eden. It’s light spread to all direction and from it comes the lower Eden. The lower Eden gives birth to lower Chokmah and this light is revealed in Zeir Anpin and Malchut.