Abba, "father" in Aramaic, is the partzuf of Chokhmah. Shaar HaKlalim links him to the yod of the Name: "the reality of Abba is the yod of the Name, and the tip of the yod is Arich Anpin." The yod is the smallest letter, a point barely extended; the same passage describes Ima as the letter that receives all of Abba's lights and holds them.
According to Etz Chaim, it is up to Abba that the light of the Infinite is revealed without a screen: "up to here the Infinite is revealed, up to the thought called Chokhmah." From this comes the verse "You made them all with wisdom": all of Atzilut is made in the secret of Chokhmah, and Abba spreads and clothes himself in all of it to give it life. On the ladder of the soul, Abba corresponds to the chayah, life.
Where does he come from? Shaar HaKlalim teaches that Abba is formed from the right arm of Arich Anpin, Ima from the left arm, and that their two crowns come from his throat. His nourishment comes from the eighth arrangement of Arich Anpin's beard, notzer chesed, "who keeps kindness." Etz Chaim further specifies that Abba divides into two partzufim, Abba and Yisrael Saba, and Ima into Binah and Tevunah.
Above all, Abba never goes without Ima. Shaar HaKlalim quotes the Idra: they "go forth together, dwell together, and never part." Their first union takes place without anything rising from below, "only by way of kindness," as it is said: "the world is built by kindness." Etz Chaim details five differences from the lower couple, Zeir Anpin and the Nukva: Abba and Ima have the same stature, they always stand face to face, their union is constant, they are always mercy, and they are always embracing. Their union that gives life to the worlds never stops, "so that the worlds not be annulled."
Cordovero, who reads the Idra in his own way, says the same of Chokhmah and Binah: their union "never parts," and that is why the Shekhinah must sing constantly, while the union of Tiferet and Malkhut takes place only in the morning, at the hour of prayer. For him, Abba and Ima are the Sefirot Chokhmah and Binah themselves, which Da'at, coming from Keter, unites with each other.
Keep the role of the yod: a point so small that it can do almost nothing alone, but which Ima receives, holds and develops. In the language of the Ari, wisdom never parts from the understanding that receives it.
