Like the Shekhinah, the divine soul descends into exile–into the body–with the purpose of raising the elements of holiness in the body and the vital soul.
Because the divine soul is pure, a portion of God above, it does not require purification and elevation.
It descends into the lowly, impure body solely to carry out its mission: to bring forth the good and rectify the body and all that relates to it in this world, so as to gather and raise the elements of holiness.
And so the greater a portion of the world that a mitzvah affects, the more inclusive it is.
The more it touches on the materiality of man and the world, the more fully it fulfills its role.
In the light of the above, one can understand why our Rabbis, of blessed memory, so strongly emphasized "the virtue or mitzvah of charity," declaring that "it balances all the other commandments."
Charity is not the only mitzvah described as being equal to all the other mitzvot.
This statement must therefore be understood as coming out of a certain context.
In a sense, the totality of the mitzvot constitutes a complete whole in which each mitzvah has a role shared by no other.
Yet there are some outstanding mitzvot in which the more generalized part of its relation to the whole complex of mitzvot is clear.
Charity is one such mitzvah.
As our sages teach, it is one of the pillars on which the world stands (Pirkei Avot 1:2).
And throughout the Yerushalmi Talmud it is called simply "the Commandment."
In the Yerushalmi Talmud, whenever the word mitzvah is mentioned without qualification, it is a reference to charity and its offshoots (Peah 8:9 and elsewhere).
Because it is the core of the precepts of action and surpasses them all.
–Rabbi Adin Steinsaltz
From Understanding the Tanya, p. 271, by Rabbi Adin Steinsaltz