Primordial Free Choice \ Ohr HaChaim HaKodesh
“After HaShem rejected Kayin’s inferior sacrifice, Kayin was very saddened. HaShem said to him (Bereisheit 4:6-7), “Why are you angry and why are you sad? If you will transform yourself to be good everything will be elevated.”
Two questions arise: One, since HaShem rejected Kayin’s offering, he had good reason to be melancholy. If so, why did HaShem ask him, “Why are you angry and why are you sad?” Secondly, the phrase “If you will transform yourself to be good” is written in the future tense. How will uplifting himself in the future, rectify the past?
The essence of free choice is "how man defines himself." HaShem commands us to define ourselves as “good”. We have the option to fulfil this axiomatic precept or dismiss it.
Defining ourselves as “good” is the primordial Mitzvah and the source of all ethics. When we exercise our free choice and define ourselves as good, we activate and empower the innate goodness of our Holy Souls. Once we do so, we become an entity of goodness, and every action that we have done in our lives converts to good.
HaShem asked Kayin, “Why are you angry and why are you sad,” because Kayin never activated his free choice to define himself as “good.” If he had defined himself as “good” there would be no reason to be "angry and sad." By establishing himself as an entity of goodness, he would have transformed his offering to be "pleasing to HaShem."
Let us understand the significance of fulfilling the core Mitzvah of “defining yourself as good.” If we do not exercise our free choice in this realm, our essence and all of our misdeeds will remain negative.
On the other hand, if we do define ourselves as an entity of “goodness,” our essence and all of our actions — past, present, and future — will be positive, worthy, and pleasing to HaShem.
Envision Avraham Avinu choosing to view himself an entity of goodness, holiness, and joy.
(Based on the commentary of the Ohr HaChaim to Parashat Bereisheit)