Answer

In all three sets of sefirot, the first is the initial expansion (kindnesses), the second is the form given to that expansion (its limitation—judgments / powers of restraint), and the third is the product of combining the first two. Thus da’at is the combination of wisdom and understanding, and Tiferet is the combination of kindness and Gevurah. In short, think about the description of our forefather Abraham slaughtering three calves in order to feed the angels who came to him tongues with mustard. That is obviously completely unreasonable (especially in a world without refrigerators, where all the meat would spoil). Couldn’t he just have given them a drumstick? That is kindness not limited by justice. Pure kindness cannot appear in the world (it is neither sensible nor proper to act that way). For kindness to have meaning and logic, and for it to be something one can live by, it must be limited by justice (Gevurah). Only the combination of the two can run the world in a complete (= glorious) way. Tiferet is that wholeness: a proper and complete integration of kindness with justice. That is why Jacob was the choicest of the patriarchs, because he embodied Tiferet. Rashi on Genesis explains that the Holy One, blessed be He, wanted to create the world with the attribute of justice (Elohim), and saw that it could not endure, so He combined it with the attribute of mercy (the Tetragrammaton), and thus the name “the Lord God” appears in chapter 2 of Genesis. Why didn’t He create it with pure mercy? Because that wouldn’t have worked either, just like pure justice wouldn’t. Only the combination can function in a realistic world. Pure kindness is being a sucker; that is not the right way to conduct oneself in our real world. Absolute justice means doing only what one is strictly obligated to do, without kindness. The combination is what should guide us.