אמר רב חסדא ואיתימא מר עוקבא כל אדם שיש בו גסות הרוח
(.אמר הקב”ה אין אני והוא יכולין לדור בעולם (סוטה ה
The Tanya in the sixth chapter explains the severity of arrogance. The path to holiness is by surrendering ourselves to Hashem, because all holiness stems from Hashem and Hashem bestows holiness only to those that surrender to Him. The purpose of Torah and Mitzvos is to help us achieve it. Somebody that is arrogant is severing themselves from Hashem and from holiness. In particular is detriment somebody who exploits Torah and Mitzvos for their own arrogance, in opposition of their true purpose which is to attach ourselves to Hashem.