The Name Elokim is the Name indicating the attribute of Gevurah and tzimtzum. Each of G‑d’s Names denotes a particular Divine attribute. The Name pronounced Keil is the attribute of Chesed. The Name that indicates the attribute of Gevurah or tzimtzum is Elokim; i.e., when the light of the Ein Sof garbs itself in Gevurah to bring about its own tzimtzum and concealment, it is known by the Name Elokim.
It is also numerically equal to hateva (nature) or 86. “Nature” signifies the ordered way of the world. Because it's repetitive, we're accustomed to it and take it for granted. We're not conscious of the Divine power and life-force concealed in those things which have an established order and are repeated constantly.
The Name Elokim conceals the light that brings the world into existence. The supernal light constantly creates the world ex nihilo but Elokim conceals this light, so that it's invisible to created beings, so it looks as if the world exists — without having to be constantly renewed, as if permanently programmed — and is conducted according to the laws of nature, independently of any supernatural influence. Thus, even those things which are observed to undergo some degree of renewal are also perceived as “the way of nature,” inasmuch as they follow these seemingly immutable laws.
The word טבע (“nature”), can mean “entrenched” and “submerged”. This means that the laws of nature are so “entrenched” in creation that it is difficult to detect the ongoing process of its renewal. Also, just as a submerged object is completely concealed by water, so, too, is the Divine life-force utterly “submerged” and concealed within created beings.
And this Name Elokim, not as it exists in its supernal source, but as it acts through the attribute of Gevurah, so that the world appears to be conducted in a natural manner, is a shield and a sheath for the Name Havayah, The Divine Name Havayah is like the illuminating sun, while the Name Elokim conceals its light as does the sun’s shield, thereby enabling created beings to benefit from it. It conceals the light and life-force which flows from the Name Havayah and bringing creation into existence from naught, this being the purpose of Havayah, the Name itself meaning “to bring into existence.” This light and life-force is concealed by Elokim, so that it should not be revealed to the creatures, which would thereby become absolutely nullified.
It is only through the concealment effected by the Name Elokim that created beings are able to exist.
The quality of this Gevurah and tzimtzum is also an aspect of Chesed, through which the world is built. This is an allusion to the verse that states: “For I declared that the world be built through [the attribute of] Chesed.” For inasmuch as the world could not possibly have been created without the tzimtzum and concealment afforded by the Divine Name Elokim, it follows that the ultimate intent of this tzimtzum is actually Chesed.
And this is the quality of Gevurah which is included in Chesed. I.e., this is a form of Gevurah through which an act of Chesed is accomplished. As such it is included within Chesed.