Genesis 49:5 - Joseph Benson’s Commentary on the Old and New Testaments

Simeon and Levi are brethren In disposition, but unlike their father: they were passionate and revengeful, fierce and wilful; instruments of cruelty are in their inhabitations, or, as מכרתיהם mecherotheihem rather signifies, their counsels, or compacts, alluding to their treacherous agreement with the Shechemites: their swords, which should have been only weapons of defence, were (as the margin reads it) weapons of violence, to do wrong to others, not to save themselves from wrong.