Musar sobre Exodo 21:28

סקול יסקל השור ולא יאכל את בשרו. The ox must be stoned, and its meat must not be eaten." Rabbi Menachem Habavli explains that the reason for this injunction is that once the verdict on the ox has been pronounced, i.e. that it is to be executed, its flesh is automatically forbidden, just as we have the rule that כל שעתיד להשרף כשרוף דמי, that anything that is to be burned, is considered for legal purposes as if it had already been burned. Anyone who has become the instrument of harm or death to a third party becomes detested and one must not derive any benefit from such person or thing. Such a person's fate is to be "consumed" by others. A שליח לדבר עברה, someone designated to perform a transgression, can no longer serve as עץ מאכל, a fruit-bearing tree.