Musar su Levitico 18:5

We always proceed from the premise that all of Israel is considered נפש אחת, a single soul, life-force. Israel as a whole is called by the title אדם. As a reminder of this fact the family members of Jacob, 66 in number, who moved from the land of Canaan to Egypt in Genesis 46,26 are referred to as נפש, soul, or person, in the singular. Just as a body possesses 248 limbs, so the Jewish national body, known as אדם, comprises a great number of parts. The Zohar refers to these parts as שייפא דגופא, shavings or splinters of a body There are, of course, different levels of importance among the various parts of a regular body. The same is true when we describe the parts of the body which make up the Jewish nation. There is a head, a heart, an eye, a hand, etc. However, just as all the parts of the body combine to make a whole human being, so all the parts of the Jewish nation combine to make it one unit. The unit created by these many parts in turn combines to form the chariot, מרכבה, of the spiritual counterpart of terrestrial man in the Celestial Regions. This celestial אדם is perceived as sitting on the throne which is one of the 248 spiritual limbs that form the root of the 248 positive commandments, which, if performed by terrestrial man, are his true source of life (אשר יעשה אותם האדם וחי בהם Leviticus 18, 5).

And the ninth level is the severity of the sins for which one is killed rather than transgressing them: Our Rabbis, may their memory be blessed, said (Sanhedrin 74a), “[With regard to] all transgressions in the Torah, if a person [is told], ‘Transgress and you will not be killed,’ he may transgress and not be killed, [...] as it is stated (Leviticus 18:5), ‘[You shall keep My statutes and My judgments,] which a person shall do, and he shall live by them’ - ‘and live by them,’ and not to die by them,” except for idol worship, forbidden sexual relations, and bloodshed. For if a person tells him about one of these three, “Transgress and you will not be killed,” he must [let himself] be killed and not transgress - even when they tell him to do the transgression in private; [whereas with other sins, such a law would only apply in public,] as it is stated (Leviticus 22:32), “that I may be sanctified in the midst of the Israelite people.”

And from this one can reflect how he must be heedful of all the 613 mitzvoth with all his strength in the days of his life. For it is they [the mitzvoth] that extend his life eternally in the organs and sinews of his soul. As it is written (Vayikra 18:5): "And you shall keep My statutes and My judgments that a man shall do and live in them." It is not written "And he shall live because of them" [but "in them,"] to teach that the light of the mitzvah itself is his life in the world to come — just as one wishes to be perfect in all of his limbs in this world, so that he not be blemished in his very smallest organ.