Eliezer Abrahamson: Because it is murder.
Moshe Kerr:
Isaiah’s prophetic mussar commands: DO NOT make a barbeque unto Heaven. Either swear a Torah oath while standing before a Sefer Torah OR swear a Torah oath while standing before the Altar when the Cohen casts the living blood holy to השם. The substance of korbanot and tefillah – the dedication of tohor middot holy לשמה.
Murder stands as a completely different commandment. The test of the Akidah did not stand on the foundation of would Avraham murder Yitzak? But rather it defined the oath which Yitzak swore unto השם: deliver the seed of Avraham from Shoah and that chosen Cohen seed dedicates to do mitzvot לשמה, the first Sinai commandment!!!
What defines the faith of doing mitzvot לשמה? The Torah commandment (תמיד מעשה בראשית), capable only within the oath sworn lands of conquered Canaan צדק צדק תרדוף, justice justice pursue.
Neither the Court of Par’o in the days of Moshe nor any European court in the last 2000+ years of Jewish refugee g’lut, never did any European court rule with justice. Torah faith shares no common ground with avoda zarah theological creed belief systems, which demand and determine exact what believers must believe in this or that God.
The Mishna teaches that the Man who asks that which exists “above”, “below”, or “behind” him, better that such a Man never born! Gods, Satan, and the physical Creation of the world and messiah utter tumah avoda zarah. Israel came out of the oppression of Egyptian slavery with the intent to conquer Canaan and rule the land with righteous tohor justice. Herein defines the k’vanna of Torah acceptance and faith. Just that simple.
Conflict Resolution 