The severity of Rabbinical transgressions:[1] Although Rabbinical commands and decrees were not directly commanded by Hashem and the Torah, transgressing them is very severe, and has spiritual effect just like a Biblical transgression. The Alter Rebbe states in Tanya that one who transgresses even a light Rabbinical prohibition is separated
Although Rabbinical commands and decrees were not directly commanded by Hashem and the Torah, transgressing them is very severe, and has spiritual effect just like a Biblical transgression. The Alter Rebbe states in Tanya that one who transgresses even a light Rabbinical prohibition is separated from G-d for that very moment of the sin, just like by actual idolatry.