The Sefirot can be seen as being manifestations of the Divine unity and not only as vehicles or instruments of His will.
To be more specific, let us see what happens when a certain aspect of Infinite Light clothes itself in the Sefirah of Chesed.
In the Tikunei Zohar, Chesed is called "arm," that is, an organ and a vessel for the grasping and distribution of Light.
The ray of Infinite Light (which is "clothed" in it) is not a particular light, it is a general light, but in the Sefirah it takes on the particular quality and tone of the Sefirah.
As some ancient texts have described it, the situation may be likened to pure water that assumes the color of the glass receptacle into which it has been poured, so that one sees green water, red water, or whatever, without there having been any change in the composition of the water.
The water remains clear and colorless.
So it is with the Infinite Light that vivifies one Sefirah or another.
It does not become something else, it is still of Divine and unqualified essence even when it assumes the particular "color" or quality of a Sefirah.
Thus the mitzvah of charity and loving-kindness is an expression or irradiation of the Sefirah of Chesed, bringing Divine Light down into the world.
When one fulfills this mitzvah of charity, the hand that offers the free gift is the hand of God.
It is God who is bringing down loving-kindness through the agency of the human hand.
Just as, in our daily prayers, we repeat the supplication phrase to God, "who brings down the rain," and at the same time, realize that it is not a miraculous intervention in nature but that clouds and wind and temperature are conjoined to act as agents for the blessed downpour.
In this sense, incidentally, Divine chesed is often depicted as rain, with a particular person-like a wind-borne cloud-acting as His instrument.
The element of self-nullification is here very important, because the act of giving charity is valid only when a person is connected to a source (when he does not feel himself as the doer), when he feels that his hand is an implement of a Divine wish, and he himself is in some way or other eliminated.
He has become an indirect instrument of something else and has somehow been separated from the act.
The hand that gives charity is not his.
At the same time, when he is connected with God, he is conscious of what is happening, he takes part in the loving-kindness behind this giving of charity, paying proper attention to the one who is in need of it.
Whatever the circumstances, when Chesed, Divine Grace, is asked for, it is somehow obvious that it will be vouchsafed through some earthly agent, if for no other reason
than that it should be possible to receive it.
Otherwise, the grace is liable to be too much for us.
We need the restricting power of Gevurah to limit it to suit our needs.
Our prayer for rain belongs to the second, the Gevurah aspect of the benedictions, because it might easily become a flood if not contained, limited, and kept within bonds.
For we cannot bear too much chesed and goodness, or gevurah, for that matter, or excess of any kind.
We live within a very circumscribed range of conditions: temperature and atmospheric
pressure, human pity, and power .
Too much of anything is disastrous, and therefore, Chesed and Gevurah have always to be mixed and merged.
Love has to know its limits, strength has to be permeated with compassion.
As it is written: "Who is the hero-he who conquers his impulse (Pirkei Avot 4:1).
Our prayers have this quality of gevurah, of offering ourselves up instead of making sacrifices in the Holy Temple.
But actually, it is easier to get hold of some animal, to bind and slaughter it, than to
catch hold of one's own inner drives and impulses.
And when a person does this offering up of himself in an act of overcoming his impulse, breaking his wild spirit, so to speak, it belongs to Gevurah.
–Rabbi Adin Steinsaltz
From The Candle of God, “Sanctity and Restraint”, p.123, by Rabbi Adin Steinsaltz