However, Chessed, Gevurah and Tiferes have an innate, essential connection with Malchus. Malchus: That is then why any physical, actual effect Chessed, Gevurah and Tiferes have is accompanied by the energy of Malchus as it is essentially intertwined and included in the former Sefiros.
Thereafter: Only after Malchus is put into effect as it is lodged within the first three emotive attributes, only after it is utilised and simultaneously comprised in Chessed, Gevurah and Tiferes.
Individually: With all this Kabbalistic interpretation, we can fully understand why there are three Biblical blessings in ‘Bentching’ and then thereafter an additional Rabbinic blessing. Because the first three Biblical blessings correspond to ‘Chessed’, ‘Gevurah’ and ‘Tiferes’ which all naturally possess an element of ‘Malchus’ in their core but then the additional Rabbinic blessing corresponding to Malchus is as it is on its own, removed from the three basic strands. Why? Because although the message of the fourth Blessing “Hatov Vehamaitiv”, is already mentioned and discussed in the first three blessings, (Which is why from the Torah a fourth blessing is not required); just like in the Sefiros! Nevertheless, the Sefira of Malchus has an additional effluence when on its own, individually. Compared to the fourth, additional blessing. So It’s always there, mentioned and repeated in the first three blessings naturally, and only after the first three blessings can it be listed again, but it’s not biblically mandated.
Regarding the Supernal Chariot
It is known that the supernal chariot has primarily three legs which correspond to the patriarchs Avrohom, Yitzchok and Yaakov and only later on is a fourth leg added which corresponds to Dovid Hamelech who represents the state of ‘Kingship’. Similarly, regarding the elements from which the substance of the world is made. According to Kabbalah, the Universe is consisted of a combination of four basic elements: fire, air, water and earth. Every material and spiritual being consists of a unique combination of these four elements. Each of the four basic elements of the material world has fundamental characteristics, which are expressed, for instance, in its gravitational pull, temperature, state of mass, molecular density, dissemination and motion in space and so forth. Thus, these basic elements are clearly much more fundamental than the elements on Mendeleev's Periodic Table, which is used in chemistry. The behaviour of the basic elements in the physical dimension also teaches us about their characteristics in the spiritual dimension, as well as their appearance and activity in the human mental forces. (adapted from Chabad.org)
The Sages designated specifically the Patriarchs as Hashem’s chariot, although every Jew’s body becomes a ‘chariot’ when he performs a Mitzvah, because the Patriarchs’ submission to the Divine Will was unique in its power, its scope, and its consistency. All their limbs were totally surrendered to the Divine Will throughout their lives — whereas with other Jews, only those limbs which perform a Mitzvah are a ‘chariot’, and then only during the act. In fact, the same limb which today served as a “chariot” to Hashem’s Will might conceivably serve the opposite purpose tomorrow.
Just as in the previous cases, there is already completion with the number three, but missing Malchus as an individual entity. And only after Malchus is revealed through the first three can it be added alone as an independent entity. It isn’t a coincidence that Malchus means Kingship and sovereignty and the fourth leg of the Chariot, was designated for Dovid Hamelech.
